Ballastless Track

Infrastructure Commission – Civil Engineering Support Group

Feasibility study « ballastless track »

Report - March 2002

UIC Infrastructure Commission Civil Engineering Support Group Feasibility study « Ballastless track » - Version : 08/04/2002

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This report has been prepared with the following people help: - Marcel FUMEY

project manager

( RFF / SNCF )

Track Experts / general practitioners : -

Christoph HOFMANN Rudolph SCHILDER Paul GODART Jean Marie TREVIN Tomas ŠIMOVIČ Michael MIßLER F KLÖSTERS

( SBB / CFF ) ( ÖBB ) ( SNCB ) ( SNCF ) ( ZSR ) ( DB ) ( NS Railinfrabeheer)

Structure Experts : - Stefanie CRAIL - Roman FILA - Dominique MARVILLET - Lourdes PORTA

( DB ) ( ÖBB ) ( SNCF ) ( RENFE / TIFSA )

UIC representative: - Peter ZUBER

(UIC Infrastructure)


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CONTENT Foreword

4

First part: Generalities on the ballastless track I. 1 Recall on functionalities of the track

5

I . 2 Case of application of the ballastless track I . 3 Mains differences between ballastless track and ballasted track I . 4 Rail fastening systems and resilient levels I . 5 Process of obtaining of the final geometry I . 6 Replacement of elements I . 7 Specific problems to ballastless tracks on earth work I . 8 Specific problems to ballastless tracks on railway bridges I . 9 Specific problems to ballastless tracks in tunnels I . 10 Specific problems to ballastless track switches and crossings I . 11 Transition constructions I . 12 Secondary problems

6 7 9 11 13 14 16 17 18 18 19

Second part : Catalogue of ballastless tracks II . 0 Classification

20

II .. 2 1 Family Family 2 1 :: systems systems without punctual fixingsof ofthe therail railand independent II with punctual fastening stretches of rail II . 3 Family 3 : systems with punctual fastening of the rail on sleepers incorporated in structure by infill concrete II . 4 Family 4 : systems with punctual fastening of the rail on sleepers incorporated in structure by vibration II . 5 Family 5 : systems with punctual fastening of the rail on sleepers laid and anchored on a supporting structure II . 6 Family 6 : systems with punctual fastening of the rail on sleepers separated from supporting structure by a resilient level II . 7 Family 7 : systems with punctual fastening of the rail on prefabricated slabs

22 24 35 39 40 45 48

Third part : Potential studies about ballastless track III . 1 Works to complete the state of the art of ballastless tracks III . 2 Elements of requirements


54 59

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Project : Feasibility study « Ballastless track »

Foreword

The feasibility study " ballastless track " has for goal to provide to networks participating in the project a state of the art on the topic of the ballastless track last. The report of this study is divided in three parts: - The first part " generalities " regroups all general considerations, that may influence the choice of a ballastless track - The second part “catalogues " briefly describes the different present realisations regrouped by families - The third part " potential studies " regroups topics that can make the object of harmonisation works in the setting of a project of the UIC Infrastructure Commission. In the first part it is shown that there is not a single solution for ballastless track but different solutions that can present some specific advantages according to projects. One endeavours in this part to clear reasons that can drive to the different technological solutions. Filigreed of this part there is the comparison with ballasted track that remains the reference solution , in relation to which the ballastless track can bring advantages in certain domains. The second part proposes a classification of the different known realisations with a succinct description for every product indicating its level of utilisation. At last in the third part one examines the potential studies on the topic " ballastless track " that could be steered and financed by UIC and one gives out propositions. This report applies to full railways with axle load up to 22.5 t but not to metro systems. The main experience is for plain track ; experience with bridges and switches is less available.


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Project : Feasibility study « Ballastless track »

First part: Generalities on the ballastless track

I. 1 Recall on functionalities of the track

The main function of the track is the servitude of the vehicle (train) to a trajectory (track alignment of the civil engineering). This mechanical function requires to maintain the system in an elastic working domain: limited stresses, no plastic distortions that would lead to some unacceptable disorders. It results in the obligation of geometric precision of the assembly of the system and in the necessity to transmit efforts exercised by vehicles toward the infrastructure support. As the vehicles source may be not perfect and can exercise some important dynamic efforts, the track system must include some elasticity and some damping to support these efforts merely to an acceptable cost. Reciprocally the geometry of the track being never perfect vehicles must include levels of sustaining to let acceptable the guidance for freight or passengers; ballastless track by a better maintenance of geometry in the time is susceptible to reduce the dynamic efforts between track and vehicles. In addition of its main function of guidance and support, the track presents other functional properties: - compatibility with the other subsystems (signalling for example) - environment: noise, vibrations and recycling complexity - faculty to reach objectives of construction with more or less of efforts and quality - maintainability: consistence of the maintenance and repair feasibility - tolerance to the exceptional events: repair in case of derailment, adaptation of geometry in case of movement of the support - costs and construction time. Choices introduced in the different solutions include advantages and inconveniences according to the secondary functionalities. For example the use of sleepers introduces some supplementary components that increase costs and thickness, but permits to get the gauge and the inclination of rails in a simpler way that without sleepers. The retained compromise validity cannot be proved immediately for systems claiming life spans 40 toto60 years, reached system by any which of the all different realisations. the track itofis about necessary admit thatnot it isyet a complex links and reasons ofFor ageing are badly controlled, and that the best compromises are only revealed to the use.


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I . 2 Case of application of the ballastless track

Among sources of effort, the gravity (axle load) constitutes a preponderant factor. If the infrastructure supporting the track is a natural ground, the necessity to reduce constraints on the ground at an acceptable level obliges to include in the structure some foundation layers between the support ground and elements insuring the geometrical maintenance of the rail (fasteners and possibly sleepers). On the other hand if the support is a clearing structure (tunnel or railway bridge) intermediate layers have only a role of obtaining the geometry without distribution of the vertical load. The designation ballastless track can therefore cover different nature structures following the existent support and it is normal to distinguish cases of application following the nature of the support. For railway bridges , on the one hand the wish to separate the structure of bridge properly told (tightness for example) and the structure of track, and on the other hand phenomena of interaction between track and bridges, drive to solutions more complex than in tunnel with foundation raft. On the other hand switches and crossings do not bring particular problems compare to plain track ; of course the technology of fastening components has to be adapted to the ballastless track. Therefore 3 cases of application of ballastless track are to be distinguished : - on earth works - on railway bridges - on foundation raft of tunnel.


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I . 3 Mains differences between ballastless track and ballasted track

It seems obvious to tell that the main difference between ballasted track and ballastless track is the ballast itself. Fundamentally the ballast has a function of load distribution between sleepers and support, associated with stiffness and damping characteristics. The ballast presents also characteristics of plasticity that are both advantages and disadvantages.

Ballastless track permits to avoid the disadvantages of the plasticity of the ballast linked to its instability : - middle term evolution of the geometry that needs periodic intervention (frequency range from 0,5 to 6 years ) - wear of the ballast by abrasion and fragmentation driving to duration of life in the order 30 years ( according to traffic) - limited lateral resistance imposing particular rules for C.W.R. track. On the other hand ballasted track keeps advantages of the plasticity of the ballast linked to the facility of use : - cadence of track laying more rapid than with ballastless track with ability to traffic without delay - no difficulties to obtain the geometry of track desired with a process comprising several passes( toofweak construction as necessary cost) and the possibility to undertake as much local retaking - simple adaptation to uncontrolled evolutions of the support : settlements in the long term, differential settlements at railway bridge ends - simple adaptation to modification of track alignment : change of characteristics of switches and crossings, adaptation of transitions and the cant for speed upgrade - regeneration process well known and allowing the keeping of circulation with restrictions. Globally the plasticity of the ballast leads to the necessity of a periodic maintenance of the geometry and a duration of design life clearly shorter than with a ballastless track. Others properties can be associated with the ballast : - disadvantages linked to projections of ballast and to imprints on rails - advantages linked to the sound propagation (attenuation) - contribution to the drainage of the track. With ballastless track a better control of the stiffness of the track is achieved; if control of the stiffness is achieved, this can reduce some problems like rail corrugation.


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Designs of ballastless track avoid obviously all disadvantages of the ballast and have on the other hand to propose technologies that allow to reach initial geometry objectives to acceptable costs. The current multiplicity of solutions for ballastless track expresses several problematical : - design choices: for example the realisation of the stiffness through one or several components, or the number of replaceable components, or possibilities of adjustment in maintenance - technical and economical choices on the manner to build the structure and to obtain the geometry - technological evolutions to improve initial concepts : for example connection between sleepers and supporting structure in German monolithic layout. Nevertheless all solutions of ballastless track go in the same direction compared to the ballasted track: - to favour the availability to short term of the track (intervals of maintenance) as compared to its availability in case of accidents or reconstruction to the expiration of life - to reduce costs of maintenance by admitting greater costs of building - to concentrate investments to the expiration of life duration instead of to display them with intermediate partial regeneration.

The economic statement would have to be made project by project by integrating the cost of paths to disposition of the maintenance ; this last recommendation is more theoretical than practices. Technical considerations specific to each project can modify conditions of the economic statement : the differential of building is less great on railway bridges or tunnels than on earth works ; consequently a project comprising a majority of the layout in tunnel or viaduct is more favourable for the choice of the ballastless track. On the other hand the presence of grounds with too much long term settlement can make difficult and expensive the choice of the ballastless track.


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I . 4 Rail fastening systems and resilient levels

I . 4 . 1 Generalities If one excepts the layout with continuous embedded rail (Edilon, Infundo),ballastless track layouts use rail fastening systems (in the senses of the European norm EN 13481). In ballasted track the resilience (stiffness and damping) is obtained by combination of the of the theballast pad between and sleeper ( indicative stiffnessis of kN/mm), the stiffness of and the rail stiffness of the support. This static last stiffness not80 well controlled. In ballastless track one strives to better control the stiffness, the support structure (slab) being considered as rigid compared to stiffness like railpad stiffness. I . 4 . 2 Obtaining of the vertical stiffness Some types of ballastless tracks ( for example STEDEF layout) have a design presenting the most analogy with the ballasted track with a sleeper separated of the support slab by a resilient level equivalent to the ballast and to an average subgrade (indicative static stiffness of 25 kN/mm by sleeper head). In this case the rail fastening system can be a standard system for ballasted, for example Vossloh W14 or Pandrol Fastclip, etc ... For systems including a sleeper integrated to the support slab ( monolithic type) one will use functionalities of the fastening systems for gauge and inclination adjustments of the rail ; nevertheless to obtain a globalwith static stiffness order 20the kN/mm is necessary to use a fastening system compatible this value. in Fortheexample systemit Vossloh IOARV300 fills this condition with clips and a railpad different from the standard system W14. The system IOARV300 is classified in the second part " 2 elastic levels with light intermediate " because it comprises two pads and an intermediate plate to obtain the weak vertical stiffness while limiting the stiffness of lateral tilting over of the rail. The concept " 2 elastic levels with light intermediate " is also found in ballastless tracks with plates. One finds there generally a standard fastening system between the rail and an intermediate plate, and a second elastic level under this plate to obtain the desirable global stiffness. This second level, as it must insure transmission of the transverse and longitudinal efforts, has to be designed as a fastening system, with prestressing of the inferior pad possibly. Concepts with more than 2 resilient levels are possible.


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I . 4 . 3 Adjustable fastening systems A functionality that one can find in option in ballastless tracks is the possibility of adjustment of the fastening system. In ballasted track this option is without pertinence because adjustments of geometry undertakes by rehandling of the ballast. On the other hand in ballastless tracks the possibility to undertake adjustments of the rail in height and/or in transverse position allows to face local and limited disorders of the support structure without having to rebuild the structure. Adjustable fastenings make easier the replacement of rails, especially for rails submitted to wear under service condition. Consequently this option is necessary. In the IOARV300 system this possibility of adjustment is obtained by change of some components of the system ( lateral stops, different thickness pads). In systems with plates the adjustment in height can be obtained enough simply by interposition of shims under reserve that anchors in the support slab are anticipated consequently ; the lateral adjustment can be obtained by systems of eccentrics on the fixing of the intermediate plate or better again by utilisation of an adjustable plate in first level. The Pandrol VIPA system constitutes an example of this last case ; it includes a standard fastening system between the rail and the intermediate plate, an elastic fixing system between intermediate plate and inferior plate, a non resilient adjustable fixing between inferior plate and support slab. Adjustments undertake by interposition of shims under the inferior plate and with a system of notches associated to a light in lateral on fixings of the inferior plate ; the advantage in this last case is that adjustments of geometry undertake independently from resilient levels. I . 4 . 4 Various In the embedded rail layout (Edilon, Infundo) one has a single continuous vertical stiffness. A too weak stiffness of lateral tilting over the rail is avoided by applying an elastic supporting on all the height of the web of the rail, the head remaining released for operations like grinding of rails. On principle this mode of fixing of the rail is not adjustable in the slab; according to NS experience these interventions are seldom and special methods are available Resilient levels can be used also for other aim than the global stiffness of track for rolling stock.


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I . 5 Process of obtaining of the final geometry

I . 5 Process of obtaining of the final geometry The manner to obtain the final geometry of the rail constitutes an important factor explaining the multiplicity of designs. The order of magnitude of the tolerance is in centimetre for works of subgrade layers or structure of the tunnels rafts or decks of bridges. This precision is insufficient for the fixing of rails. therefore of have annex construction realisation of theElements geometryof,instructure additioncan of functions effort transmission. Forfunctions examplefor forthe a layout with plates above the tightness of a bridge deck one will need a concrete slab of at least 10 cm of thickness in order that this slab is stable, and allows the realisation of the cant and the accommodation of the dowels for fixings of the plate. Similarly the realisation of structures of strengthening in several stages allows to improve gradually the geometrical precision. The interface of fastening systems asks the precision notably for the inclination and the gauge of rails. A simple manner to respect the inclination and the gauge is to use concrete elements prefabricated in factory, like sleepers or slabs, incorporating the interface of fastening systems and owning far more narrow tolerances that the concrete poured on the working site. In this case there is half of degree of freedom to manage. In case of utilisation of sleepers or prefabricated slabs one can envisage two methods of constructions : -sleepers an approach " top/down " inwhose whichgeometry one fits is together rails,byfastening systems and to constitute a frame adjusted a temporary wedging system, before pouring on the site a concrete or a mortar ; structures of strengthening to insure the transmission of efforts to the support are realised before this operation (if necessary) ; - an approach "bottom/up " in which several layers of strengthening structure are installed while improving the geometrical precision before laying sleepers above them ; these layers can then be in asphalt ; if the vertical effort transmission realises easily , the horizontal effort transmission necessitates then particular disposition like anchors ; manufacturing tolerances of sleepers or prefabricated slabs if they are in concrete do not allow easily to obtain the geometrical precision for cases of application of high speed. For layouts with plates and without sleepers or prefabricated slabs, an approach " top/down " is possible in which the plates with anchors are preassembled under rails held by devices for adjustment of track insuring the gauge, the inclination of rails and the position of the track ; then a concrete or mortar of wedging is poured around anchors. A rather " bottom/up " approach consists in realise a support slab concrete with a slip-form tool allowing to obtain an intermediate precision, then before final setting of the concrete to position the anchors of the plate by vibration in the concrete with a special tool insuring the wanted geometrical position. A possible intermediate approach consists in preassembling plates without anchors on rails , to get the good rail geometry, to drill holes through the plates to put in place the anchors with chemical sealing and to adjust the plate vertically with a mortar.


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For embedded rail layouts, the realisation of a groove in concrete being made with a precision of civil engineering, the obtaining of the geometry is actually a "top/down "method with by devices for adjustment of track and fixing of the position by the coating resin instead of the concrete. To avoid variation of the vertical stiffness linked to variation of height under rail, it is generally used a continuous pad under the rail and shims under this pad. For all " top/down " methods comprising a concrete or resin plug and a preassembling of rails, procedures of working site have to take into account the expansion of rails under thermal solicitation during the setting period. For systems using traditional fastening systems the placement to neutral rail temperature can be delayed as with ballasted track layout. On the other hand for embedded rail systems this operation needs a special process: a system is available to bring rails with a length of 800 m on the neutral temperature within 15 minutes by electrical heating with an accuracy of + 1 °C; during the setting of the pourable embedment material, the rails are kept on this temperature.


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I . 6 Replacement of elements

The replacement of components of the structure of ballastless track can be justified either by considerations of wear or foreseeable fatigue , or to repair consequences of a unpredictable event, for example wheels slipping, vandalism facts or derailment. The first component of the track is the rail submitted to : - the fatigue as all metal working cyclically - the wear by wheel contact (possibly accelerated by grinding operations) - replacements on punctual or breaking At least one replacement of rail isdefects to anticipate to mid, notably - life ofwelding. support structures (duration of life of about 40 to 60 years). The utilisation of traditional fastening systems allows to replace rails with the minimum of constraints for a programmed regeneration and with the minimum of unavailability of the track for exceptional replacements ; on the other hand embedded rail systems oblige to reconstruct partially the system including constraints linked to the initial geometry. Interest for adjustable fastenings is already mentioned in 1.4.3. Resilient levels associate generally stiffness and damping. With components like elastomers the level of solicitation, all the more raised with the proximity of the rail, could lead to an ageing linked to the damping. Components of fastening systems like lateral stops, insuring the gauge and the transverse effort transmission, can also be submitted to wear by displacement or plasticity. It is therefore advisable that components like pads, under rail or plates or sleepers, as well as lateral stops are replaceable in easy conditions because their duration of life can not be demonstrated on periods of about 40 to 60 years. Embedded rail systems oblige to reconstruct partially the system, including constraints linked to the initial geometry, for this type of operations. Taking uncertain events into account , as a localised failure of the civil engineering support or the derailment of a train following failure of rolling stock , can drive to wish to have replaceable elements in the structure under the fixing of rails . In systems with sleepers it should be distinguished layouts like rubber booted sleepers or ATD, in which sleepers remain replaceable components, and monolithic systems in which sleepers are used for purposes of setting only and are no longer separable from the support slab once the track constructed. In the first case repairs necessitate less works, in quantity and in period of intervention. It is also the case for systems with prefabricated slabs that are to be considered as replaceable components. Plates of plated layout systems are replaceable elements under reserve that anchors in slab allows it. The concern of component replacement can go until to prefer the females type anchors, like dowels associated with sleepers screws or assimilated, rather than cast-in shoulders, difficult to replace in case of corrosion or in case of damage following derailment. All this approach of choice of replaceable elements does not notice an optimisation of the sizing, but of a sensitivity to risks lending badly to an economic optimisation.


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I . 7 Specific problems to ballastless tracks on earth work

On earthwork one should state precisely the limit of what is called by the term track (superstructure) by difference with structures of civil engineering. The soil support (cutting or embankment ) is constituted of economic materials from local source. It has mechanical properties of bearing capacity and sensitivity to frost. In the general case these properties are insufficient to receive a level of loading under track (ballast or slab). Therefore in general there are sublayers in materials brought back with the controlled properties get theover wanted typical Ev2> 120 N/mm² for permitting the bearing to capacity theseproperties; layers and some a height of 70 numbers cm for theareprotection to frost. These foundation layers are practically a common element to ballasted tracks and ballastless tracks and make part of the civil engineering works. Then in ballasted tracks one finds an intermediate layer of interfacing between the ballast and structures of foundation. This layer is generally made of about 20 cm of materials type gravel with small granulometry in order to get properties of compactness towards ballast and drainage by lateral evacuation; alternative structures with geotextil and gravel are for example are also possible. The concrete sleepers requires a minimal height of about 30 cm of ballast under sleeper. The height (sleeper + rail) is about 40 cm. In a ballastless track like Rheda type (monolithic concrete) one finds a 30 cm layer of gravel treated to the hydraulic binding material. The intermediate structure type trough with infill concrete brings a thickness of about 25 cm under sleeper. The height above the foundation layers are therefore the same order that in ballasted track. Materials type concrete being more expensive in supplying in building than ballast, this type of track is necessarily more expensive than a ballastedand track. Reductions of thickness can be achieved by replacing simple layers of concrete by reinforced or prestressed concrete sized for bearing and not merely for thermal shrinking (for example Stedef pose of Neuilly in France on embankment with prestressed slab of 18 cm and 7 cm of wedging concrete under sleeper). Globally structures of ballastless tracks can appear oversized. In fact they are designed for life spans of 60 years without important strain of the soil support that would put in peril the superior rigid structures. In ballasted track the structures is flexible and therefore tolerate the settlement of the soil support ; corrections of geometry bound to the settlements of the soil support are practically negligible in relation to corrections bound to the ballast itself. As a matter of principle structures of ballastless track are systems without systematic geometry correction during the cycle of life; therefore they present a sizing for bearing capacity more demanding than in ballasted track. Besides the ballastless track doesn't admit important settlement of the soil support. It is therefore imperative that the settlement of embankments newly constructed is nearly finished at the time of the construction of the track. If this condition cannot be respected it constitutes a case of exclusion of use of ballastless track on earthwork. Zones of long-term compressible soils must be cleared in ballasted track or in ballastless track on structures like railway bridge.


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Adjustable fastening systems should not be used for continuous long-term settlements with foreseeable character. As foundations of railway-bridges are by design less susceptible to settlements than embankments around, one should adopt some particular arrangements to transitions between railway-bridges and earthworks besides (it is evidently recommended also for ballasted tracks). In a layout like Rheda one has the following widths: 2.6 m for sleepers, 3.2 m for the trough and 3.8 m for the cement stabilised support layer also used for the guidance of the slipformpaver achieving the trough. This first layer of structure must be achieved with an engine type slipform-paver piloted in topography to get a correct geometric precision. Then the overall dimension for work approaches 5 m . If it doesn't put a problem for a new high speed line with a distance between centre of lines of 4.5 m, this overall dimension of work must be studied for a line (new and moreover operated) with a weaker distance between centre of lines. Other types of structure, with plates for example, must be considered not only with the overall dimension of the finished structure but also with the size of engines serving to the building and with the processes of obtaining of the final geometry.


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I . 8 Specific problems to ballastless tracks on railway bridges

I . 8 . 1 Separation track / structure A first fundamental choice concerns the independence between bridge structure and track structure. One observes an important gap between a typical choice of metallic bridge optimised on the acoustic plan with integrated embedded rail (NS) for which that the type of track can not be changed during all the duration of life of the bridge, and the choice to construct a railway bridge for a very important duration of life independently of the type of track (CFF) for which oneduration wishes to to choose the type of track and to change it knowing that the of have life ofthe thepossibility track is much lower than that the bridge. For important length railway bridges made of reinforced or prestressed concrete a very widespread choice consists in protect the upper slab of the bridge by a tightness and to realise above a structure of track in simple support on this tightness. This leads generally to a first distribution slab of the track including stoppers for transmission of horizontal effort to upper levels of the track including rail fastenings. For metallic bridges only, questions of tightness doesn't matter ; on the other hand problems with electrical insulation between rails have to be particularly taken into account. I . 8 . 2 Track (Continuous Welded Rails) and bridge interaction. For expandable lengths the choice of the ballastless track may lead to more rail expansion joints than with ballasted track while using standard fastening system. Specific interaction studies aretotolongitudinal be made ; they can drive to recommend the use of fastening systems with lower resistance sliding. The limitation of the deformation of end of railway bridges (rotation of ends and uplifting of parts beyond bearings) that is desirable in ballasted track becomes more sensitive in ballastless track and must imperatively be covered by design rules. Admissible deflexions of spans are linked to the comfort of passengers and the ballastless track layout does not justify particular rules (this question is not independent from end deformations) ; nevertheless, to allow a possible adaptation of design counter flexure, the choice of adjustable fastening system is recommended. I . 8 . 3 Transitions between railway bridges and earth works. Transition structures that are recommended in ballasted track layout become more indispensable in ballastless track layout and must imperatively be covered by design rules. These rules concern the nature of the filling behind the abutments as well as dispositions for the (possible) interruption and the anchorage of slabs supporting the track. In principle the stiffness of a ballastless track is mainly controlled in the structure of track ; therefore there should be no problem with stiffness transition but only problems with differential settlements and deformations of extremities. The necessity to have adjustable bearing for railway bridges to compensate settlement of bearing is not general application and concerns only particular cases . UIC Infrastructure Commission Civil Engineering Support Group Feasibility study « Ballastless track » - Version : 08/04/2002

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I . 9 Specific problems to ballastless tracks in tunnels

The layout in tunnel does not put problem of structure as soon as the tunnel has a raft. Supporting layers can be reduced and limited to questions of interface to obtain the final geometry. The design has to be obviously fitted to take account for example particularities of drainage systems or electrical cable passage if necessary or other equipments. The choice of a ballastless track instead of a ballasted track reduces to the strict minimum maintenance interventions, allows condition to limit the presence of safety). personnel tunnel that means a general problem what of working (hygiene and Thein technological choice of the type of ballastless track can also be linked to policies concerning safety and especially possibility of circulation for rescue vehicles. The overall dimension can also orient the choice of some solutions for questions of size. Management of gauge during maintenance is easier with ballastless track than with ballasted track (margin of maintenance ballasted track). Constraints of gauge can render more difficult and more expensive the application of methods of construction as compared to the free air ; for example the choice of long twins tunnels for safety reasons complicates the logistics of working sites. The general reserve on the adaptation to modification of track alignment for ballastless track can be raised in tunnel where economic and technical constraints of the civil engineering do not allow to forecast modifications of track alignment even in the long term .


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I . 10 Specific problems to ballastless track switches and crossings

For switches and crossings layout in ballastless tracks the technological solution choice is more reduced than for the plain track. Solutions as embedded rails can not be used for switches. Three orientations are possible. The first solution consists in taking a switch or crossing designed for ballasted track and simply to adapt bearers to realise a layout of supports on an resilient level (for example rubber booted bearers). The second consists in retain fastenings ( intermediate track plates, sliding chairs of switches or platinum supporting crossings) possessing a typical stiffness of ballastless track and to lay them on a slab. In this last case the difficulty to obtain the geometry of all files of rail is again greater than for plain track and the most reliable construction solution remains the use of prefabricated support (including the positioning of the cast in parts) to incorporate in a concrete slab. The third consists in taking a switch with resilient fastenings , to put it on prefabricated slabs with a possible resilient level under the slabs.

I . 11 Transition constructions

A special construction is required: - between ballastless track and ballasted track - between two different types of ballastless tracks (for stiffness transition) - between plain line and switches - between bridges and plain track.


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I . 12 Secondary problems

I . 12 . 1 Interfaces with the signalling Track layouts have to take into account interfaces with the signalling and the overhead contact lines. It concerns mainly questions of site reservations for equipment, of electrical connections to the rail, of insulation between rails and of possible ground linkage of metallic reinforcements. These problems have to be taken into account but do not constitute generally a criterion of choice of the type of track. The performance of insulation between rails is mainly insured by fastening systems.inItthis is not possible to give common rules, each railway organisation having its particularities area. I . 12 . 2 Problem of the noise Ballastless track is generally noisier than ballasted track. For the problem of the noise one should distinguish the noise emitted by the track and the noise emitted by the rolling stock and partially reflected by the track. For embedded rail layout less mobility of rail can be compensated by difference in mass of the system ; for layouts on plates or with integrated sleepers the lesser mobility of sleepers compared to the ballasted track is probably compensated by a greatest mobility of the rail due to the fact of a weaker stiffness. For the question of the reflection of noise the ballast constitutes an good absorbent ; its disappearance structure of track entails an aggravation of the reflected One will find therefore of in the design of ballastless track some ballast banquettes havingnoise. a function of absorption of the noise and not of mechanical supporting. One can possibly have absorbent panels laid near rails ; this type of equipment constitutes a complementary option and is not really linked to a choice of structure for ballastless track. I . 12 . 3 Problem of ground vibrations For the problem of ground vibrations improvements can be obtained as compared to the ballasted track either by using systems of track with suspended intermediate masses (rubber booted sleepers layout for example), or by adjusting the stiffness in systems with plates. In this last case one should well verify the aptitude of fastening systems to accept not conventional stiffness . Floating slab techniques suspended with resilient level can equally be used in conjunction with ballastless track ; one should then examine stiffness transitions at ends of these realisations and the aptitude to the replacement of the resilient level under slab in connection with its duration of life.


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Project : Feasibility study «Ballastless track»

Second part : Catalogue of ballastless tracks

II . 0 Classification

There exists different possibilities to classify ballastless tracks allowing to regroup realisations whose principles and the technology are neighbours. One has retained to privilege aspects " components " and " stiffness " to end on the table of the next page


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Ballastless track Classification Rail fastenings (EN 13481) Components and building

1 without

2

Independent stretches of rail

Replaceable components Building method « top/down » « bottom/up » particular

1 resilient level

A

2 resilient levels light intermediate

B

Families 4 With rail fastening system acco Inclination and gauge for both without With sleepers

top/down resin flowed in place

top/down wedging concrete and reinforcement

Insertion of sleepers by vibration in concrete

bo 1 con 2 asp

Embeddedrail EDILON

PACT Layout with 2 levels plates

Züblin BTE

>2 resilient levels heavy intermediate

3

C

Heilit W. BES APPITRACK CrailsheimFCC Rasengleis Hochtief/SM Direct laying “booted” blocks

Monolithic layout

RHEDA Rheda Berlin RHEDA 2000 Heitkamp

ZUBLIN

G

NS Blokkenspoor

SONNEVILLE


L anc sev

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II . 1 Family 1 : systems without punctual fixings of the rail II . 1 . A : Embedded rail systems (one single resilient level)

In this family it is not used punctual fixings of the foot of the rail. The supporting structure is constituted of a slab in reinforced concrete including grooves ; grooves can be constituted of metallic profiles in case of construction on metallic deck without concrete slab. Rails are positioned in grooves then coated by a resin. The coating is generally limited in height under theisrail head to allowthethequantity grinding the and rail.toThe width of the groove is limited and a PVC pipe used to reduce ofof resin limit the transverse stiffness. The positioning of rails in levelling, lining , gauge and inclination is possible by shims in resin adjusted to demand. Nevertheless a correct and economic layout cadence would ask a method of pose with devices or adjustment of track, what would actually constitute a top/down method. The realisation of the concrete slab and grooves with an engine that can be piloted in geometry like a slipform-paver allows to hope a geometrical precision in the order 5 mm. With a nominal thickness of resin (or equivalent elastomer) of 20 mm designed to find a displacement of the rail under the wheel equal to a classic track, one is susceptible to have variations of 10 % of stiffness due to the variation of height to find the wanted level of the rail. One can not therefore consider that the embedded rail system solicits less rails in flexion than the other systems. To the does difference of traditional fastening systems thebylaw of behaviour fora the longitudinal sliding not comprise an elasticity phase followed a sliding phase but more important phase of elasticity followed by a breaking of the system. This does not allow the use on bridges with lengths without expansion joints more than 30 m. Bridges with length till 1100 m are presently under construction with this type of track. This type of laying presents advantages to process from singular points : bridges with short length, grade crossings and paved track (tramways). On the other hand for a use in great length some reserves can be emitted for operations of rail maintenance : - necessity of specific tools , difficulty of use with the size of grooves for example for the realisation of welding ; processes and tools for rail consolidation not traditional in case of rail breaking (fish-plating of rails); - long intervention periods linked to the duration of polymerisation of the resin depending on the temperature ; necessary repairing of the resin near welding with period of cooling ( connecting welding and repairing welding); - no control of the neutral temperature of the rail by a process of liberation. These reserves are not strict impossibilities. It belongs to the infrastructure owner to appreciate the rail risk. II . 1 . A . 1 EDILON CORKELAST layout This type of track has been developed on the NS network since 1974. UIC Infrastructure Commission Civil Engineering Support Group Feasibility study « Ballastless track » - Version : 08/04/2002

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Layout references : - Numerous punctual applications as Channel Tunnel - Spain : 8250 m in Attocha station (RENFE - 1992) - Netherlands : applications on bridges ; pose on earth work at Deurne (1976) then 3 km track at BEST (NS - 1998) Contacts : EDILON B.V. P.O. Box 1000 NL-2003 RZ Haarlem

INFUNDO Gmbh Pasteurstrasse 7 D-80999 München


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II . 2 Family 2 : systems with punctual faste ning of the rail and independent stretches of rail

This family doesn't include prefabricated element assuring the inclination and gauge of the two lines of rails simultaneously. The method of construction must therefore assure the inclination and gauge of rails , in general with a temporary system of connecting bars; the use of plates for the fixing of rails doesn't solve the problem of the rail positioning since it is then necessary to position anchors for plates . Some systems systems limit present a complete solution Other themselves to the directincluding layout onsupporting plates for structures applicationononearthwork. apron of bridge or raft of tunnel, with sometimes the objective of a minimum clearance in height. The interfacing between anchors and the supporting structure leads to several possible strategies of construction: - the simple setting up of anchors or reservations without assembling of track in the same way as the reinforcement of the concrete of supporting structure reveals to be insufficient with experience, because of the lack of precision; - realisation of supporting structure in several pass to get a precision of about 5mm, then insertion of anchors by vibration in the fresh concrete by a specialised machine with its own topographic references; - incorporation of fastenings in a block of concrete; installation of the track with rails and blocks and positioning before realisation of supporting structure; incorporation of blocks during the concrete pouring of structure. - previous realisation of supporting structure; positioning of rails in transverse with preassembling of plates then drilling for anchors through plates; fixing of anchors then regulating in height of rails and pouring of a wedging mortar under plates; - as previously but with machining of the concrete in height.


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II . 2 . A : Systems with a single resilient level .

This family is mentioned for memory because it doesn't present a compliant stiffness to the present norms for high speed notably. II. 2. A. 1 PACT layout The rail is supported by a continuous resilient pad. After realisation of the supporting slab the concrete is ground at the site of the rail to get the correct geometry.

References : - track in tunnel– (BR) - test track on earth work – 4 km (RENFE – 1975) - track in tunnel at Roger-Pass – 78 km (Canada – 1988)


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II . 2 . B : Systems with 2 resilient levels and light intermediate.

In this family it can be found all direct layout with two levels plates. A first level fixes the rail by fastenings like ballasted track on an intermediate plate. A second level includes a flexible elastic level between intermediate plate and a support plate or directly a slab support. In any case one will have a fixing to insert and to position in the support structure with a positioning of rail.

II. 2. B. 1 ZÜBLIN BTE layout The system includes a reinforced concrete slab (BTS) over the cement stabilised support layer (HGT). At the site of rail fixings the concrete is machined then to get a correct geometry with a two-level plate system.

References : - test track on earth work – 390 m Waghäusl (DB – 1996) Contact :

ZÜBLIN AG Hauptverwaltung Stuggart Albstadtweg 3 D-70567 Stuttgart


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II . 2 . B . 2 Heilit & Woerner BES layout The system includes a reinforced concrete slab (BTS) over the cement stabilised support layer (HGT). A two-level plate system is inserted by vibration in fresh concrete to get a correct geometry .


HEILIT+WOERNER BAU-AG Klausenberger strasse 9 D-81667 München

II . 2 . B . 3 APPITRACK layout The system includes a concrete slab over a cement stabilised support layer. A plate system is inserted by vibration in fresh concrete by a particular engine following the slipform-paver. These machines are automatically piloted for topography to get a correct geometry. System being developped – Light rail experimental track in La Rochelle ( France). Contact :

ALSTOM TRANSPORT Département Infrastructure 3, rue Eugène et Armand Peugeot F-92508 Reuil-Malmaison-Cedex


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II . 2 . B . 4 Pose Leonard Weiss Crailshem FFC The system includes a reinforced concrete slab (BTS) over the cement stabilised support layer (HGT). Dowels are inserted by vibration in fresh concrete and the interface of fastening system is adjusted by a particular engine following the slipform-paver making the slab. These machines are automatically piloted for topography to get a correct geometry. Then a IOARV 300 fastening system is assembled.


LEONARD WEISS Gmbh & Co Brunnenstrasse 36 D-74564 Crailsheim


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II . 2 . B . 5 Heilit & Woerner Rasengleis layout The system includes reinforced concrete beams above the reinforced concrete base layer. A system with a two levels plate is inserted by vibration in fresh concrete to get a correct geometry.




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II . 2 . B . 6 HOCHTIEF-SCHRECK-MIEVES layout The system includes a concrete slab (BTS) over the cement stabilised support layer (HGT). Linking anchors are inserted in fresh concrete of the slab. Then blocks including the fastening system are fastened with these anchors.


HOCHTIEF


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II. 2. B. 7 Direct layout with plates One can mention for memory direct layout examples with two-levels plates that can be used notably on bridges or in tunnel to limit the clearance in height or the weight. To get an appropriate geometry one of the strategy indicated previously should be used while taking account the local conditions of execution of the working site. A first type of realisation includes systems with an intermediate plate separated of the support by a prestressed thick resilient pad.

The NS layout constitutes an example. One can also mention the Botzelaer system of SNCB, the system Vossloh 1403 (Porto) or the layout with plate of FS. This type of layout can easily be made adjustable vertically by shims and by adaptation of anchors. The possibility of transverse regulating is much more limited and require systems of eccentrics on anchors. A second type of realisation includes systems with a plate under the intermediate plate. This plate being merely fixed to the support can easily be made adjustable vertically and transversely without modifying stiffness.


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The adjustment possibility can also be obtained by using an adjustable fastening for sleeper :


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II . 2 . C : Systems with 2 resilient levels and heavy intermediate.

In this family will be found layouts including a reinforced concrete block including a classic rail fastening system and an resilient level under and around the bottom part of the block. The method of layout comprises the installation of rails on blocks with temporary connecting bars, the positioning of rails to their definitive position and a fixing by an infill concrete or a resilient resin like corkelast. II . 2 . C . 1 Blokkenspoor NS layout

References : - track on bridges (NS – 1969/1986) - track in tunnel Schiphol (NS – 1986)

Contact :

F. Klösters Railinfrabeheer – b&i Productbeheer JCW 420 kamer 1.10 Postbus 2038 NL-3500 GA Utrecht


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II . 2 . C . 2 SONNEVILLE layout The concrete block is inserted with its bottom part in a rubber boot presenting an horizontal stiffness by mean of grooves and a vertical stiffness sole by a microcellular pad under the block.

References : - track of Channel Tunnel – 100 km (Eurotunnel – 1993) - track in tunnel – 800 m Grauholz (CFF – 1995) Contact :

SONNEVILLE


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II . 3 Family 3 : systems with punctual faste ning of the rail on sleepers incorporated in structure by infill concrete

This "monolithic" layout family includes reinforced or prestressed concrete sleepers assuring the inclination and gauge of the two lines of rails simultaneously. These sleepers are used to bring up a track grid with rails and fastening systems. After regulating of geometry, sleepers are integrated in concrete supporting structure; therefore they don't constitute the replaceable elementselements of the to definitive structure andthe necessitate reinforcement rods to prevent the prefabricated be broken away from concrete poured in situ. The track being concreted with rails, the building process must take in account the thermal expansion of rails during the setting of the wedging concrete.

II . 3 . B : Systems with 2 resilient levels and light intermediate. This family regroups layouts RHEDA type and derivatives; it uses an adjustable fastening system type Vossloh IOARV300. The system includes a concrete trough (BTS or TCL) over the cement stabilised support layer (HGT or HSB). These layers can be achieved by industrial methods drifted of the road techniques (utilisation of slipform-paver). In principle thetrough is only reinforced for thermal solicitation to get a continuous slab, except on railway bridges where it is cut up in slabs with devices for the transmission of horizontal efforts. The different solutions include some different sleeper types, some different processes for wedging and betterments aiming to improve the link between prefabricated sleepers and infill or trough concrete. For this last point the objective is to control the thermal crack opening to avoid that frost can dissociate the different elements of the monolithic structure.


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II . 3 . B . 1 Classic Rheda layout II . 3 . B . 1 . 1 The monoblock sleeper includes holes for the passage of continuous longitudinal reinforcement rods and the fixing of screw spindles for the regulating of the track with support on the trough. Sleepers are inserted by an infill concrete.

References : - test track on earth work – 640 m Rheda (DB – 1972) - test track on earth work – 400 m Dachau-Karlsfeld (DB – 1977) - track in tunnel – 334+832+470 m Hoppengarten+Herchen+Merten (DB – 1978+1979) - HS track in tunnel – 2392 m Einmalberg (DB – 1985) - HS track in tunnel – 6994 m Mühlberg (DB – 1986) - track in tunnel – 935 m Linderhaus (DB – 1987) - track on earth work – 161 m Kutzenhausen (DB – 1988) - track on bridges – 90 m Fürstenfeldbruck (DB – 1988) - HS track in tunnel – 5554 m Sengeberg (DB – 1989) - track in tunnel – 8.9 km Säusentein (ÖBB – 1993) - track on earth work – 16 km Breddin-Glöwen (DB – 1994) - HS track on earth work – 117 km Berlin-Hannover (DB – 1998) II . 3 . B . 1 . 2 The classic Rheda layout is also used with twin-blocks sleepers instead of monoblock sleeper and with longitudinal bars besides the blocks. References:

- HS track Köln-Rhein/Main (DB –2002) 165,284 km on earth work, in tunnel and on bridges

II . 3 . B . 1 Classic Rheda layout contact : DYWIDAG Dykerhoff & Widmann Aktiengesellschaft Postfach 02 80 D-81902 81 München HEILIT+WOERNER BAU-AG Klausenberger strasse 9 D-81667 München


LEONARD WEISS Gmbh Fabrikstrasse 40 D-73037 Göppingen

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II . 3 . B . 2 Rheda Berlin layout To optimise the structure, special twinblock sleepers are used with protruding reinforcement bars. The regulating of the track takes place with lost concrete wedges and a removable regulating system supporting the rail foot. Sleepers are integrated by an infill concrete.

References : - track on bridges – 16000 m Berlin (DB – 1996) - HS track Köln-Rhein/Main (DB – 2002) 54 km on earth work 30 km in tunnel 3 km on bridges Contact :

PFLEIDERER Geschäftsfeld Verkehr Ingolstädter Str. 51 D-92318 Neumarkt


SPIE ENERTRANS Gmbh Aroser Allee 62 D-13407 Berlin

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II . 3 . B . 3 Rheda 2000 layout To optimise the structure, special twinblock sleepers are used with protruding reinforcement bars. The sleepers are integrated directly in a concrete slab without intermediate trough with a light gantry system used for track regulation and as form work for concrete.

References : - HS track on earth work – 7000 m Erfurt-Leipzig (DB-2000) Contact :

GERMAN TRACK SYSTEMS PROJEKTGESELLSCHAFT mbh Warschauer Strasse 34-38 D-10243 Berlin

II . 3 . B . 4 Heitkamp layout

The trough is filled with ballast to lay the track panel; the track is adjusted by ballasted track machines. Then a mortar is flowed in the ballast to transform the track in monolithic system. References : - test track on earth work – 390 m Waghäusl (DB – 1996) Contact :

HEITKAMP Gmbh Langekampstrasse 36

D-44652 Herne


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II . 4 Family 4 : systems with punctual faste ning of the rail on sleepers incorporated in structure by vibration

This "monolithic" layout family includes reinforced concrete sleepers assuring the inclination and gauge of the two lines of rails simultaneously. These sleepers are used to mount fastening systems. In a single operation it is made regulating of geometry and integration of sleepers in concrete supporting structure; therefore they don't constitute the replaceable elements of the definitive structure. II . 4 . B : Systems with 2 resilient levels and l ight intermediate.

This family uses an adjustable fastening system type Vossloh IOARV300. II . 4 . B . 1 ZÜBLIN layout

The system includes a concrete slab over the cement stabilised support layer (HGT). A heavy tooling is positioned precisely in relation to the situation of the future track. This tooling incorporates at a time about ten sleepers by vibration in the fresh concrete . The track being concreted without rails, the building process doesn't need to take in account the thermal expansion of rails during the concrete setting. References : - test track on earth work – 233 m Obersslingen (DB – 1988) - HS track in tunnel – 4796 m Markstein (DB – 1989) - track on earth work – 12300 m Wittenberge-Dergenthin (DB – 1993) - track on earth work – 22 km Gardelegen (DB – 1996) - HS track Köln-Rhein/Main (DB –2002) 42,478 km on earth work, in tunnel and on bridges Contact :

ZÜBLIN AG Hauptverwaltung Stuttgart Albstadtweg 3 D-70567 Stuttgart


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II . 5 Family 5 : systems with punctual fastening of the rail on sleepers laid and anchored on a supporting structure

This layout family includes reinforced concrete sleepers assuring the inclination and gauge of the two lines of rails simultaneously. Towards vertical effort sleepers are merely laid on a foundation structure; on the other hand towards transverse or longitudinal efforts it is necessary that the system includes anchorage or stop devices. Links between sleepers and supporting structure being weak, sleepers can be considered as replaceable elements. For supporting structures one can find structures like road pavement in concrete or in asphalt. For the concrete structures one recovers the question of the cracking; for structures in asphalt the problematic is the one of the long-term slow distortions (vertical stamping for example), the non uniformity of which can compromise the objective of absence of geometry maintenance. Supporting structures are normally achieved in several layers to get the geometric precision of the vertical levelling. Sleepers being merely laid, their thickness tolerance and their state of inferior surface must make the object of particular prescriptions. The use of a contact interfacing on inferior face of sleepers, bidim for example, solves problems of contact but doesn't prevent from a spread of sleeper reactions owed to too strong variations of thickness.


This family uses an adjustable fastening system type Vossloh IOARV300.


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II . 5 . B . 1 BTD layout

The system includes a concrete slab poured over the cement stabilised support layer (HGT). The horizontal effort resumption is assured by an anchor rod crossing the sleeper. References : - test track on earth work – 490 m Breddin-Glöwen (DB – 1993) - HS track on earth work – 32 km Gardelegen (DB – 1997) Contact :


ZÜBLIN AG Hauptverwaltung Stuttart Albstadtweg 3 D-70567 Stuttgart

II . 5 . B . 2 WALTER layout

The system includes asphalt layers laid over the cement stabilised support layer (HGT). The horizontal effort resumption is assured by an anchor rod crossing the sleeper. References : - track on earth work – 9.4 km Hohenthurm-Rabatz (DB-1994) Contact :

WALTER BAU (see ZÜBLIN)


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II . 5 . B . 3 GETRAC layout

The system includes asphalt layers laid over the cement stabilised support layer (HGT). The horizontal effort resumption is assured by a concrete dowel held in the sleeper by a rubber bearing. The thin regulating of the lateral geometry can be assured by a lining machine for ballasted track. Then a mortar fill the space between the dowel and the groove in the upper asphalt layer. References : - track on earth work – 7.0 km Westkreuz-Ruhleben (DB-1995) Contact :

GETRAC (see PFLEIDERER)


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II . 5 . B . 4 ATD layout

The system includes asphalt layers set up over the cement stabilised support layer (HGT). The lateral effort resumption is assured by a central upstand in upper asphalt layer. The thin regulating of the lateral geometry can be assured by a lining machine for ballasted track. Then a fixing by a flexible bituminous mortar is done between the asphalt central upstand and the sleeper. Towards longitudinal effort asphalt central upstand is not directly active. The simple friction of sleepers can be insufficient in case of breaking of the continuous welded rail and the resistance sleepers. should probably be increased by putting ballast between sleepers or using heavy References : - HS track Nantenbach (DB-1993): 14,48 km on earth work and in tunnel - track on earth work – 2800 m Leinakanal (DB – 1994) - HS track on earth work – 10.2 km Staffelde (DB – 1997) A test track of 150 m was built in Strasbourg (SNCF-1996) with particular sleepers and fastening system. Contact :

DEUTSCHE ASPHALT Gmbh An der Gehespitz 20 B D-63263 Neu-Isenburg


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II . 5 . B . 5 SATO layouts

The system includes several versions with on the one hand asphalt layers set up over the cement stabilised support layer (HGT), and on the other hand Y metallic sleepers or monoblock concrete sleepers. The horizontal effort resumption is assured by anchors bound to sleepers. References :

Steel sleepers: - track Y/ATS on earth work – 635 m Welsede (DB-1986) - track Y/ATS on earth work – 793 m Hämelerwald (DB-1986) - track Y/ATS in tunnel – 935 m Linderhaus (DB-1987) - track Y/ATS on earth work – 1600 m Langenfeld (DB-1990) - track Y/ATS in tunnel – 800 m Leipzig (DB-1994) - track Y/ATS on earth work – 30km Bitterfeld-Hohenthurm (DB-1994) Concrete sleepers: - track concrete sleepers/ATS on earth work – 615 m Oelde (DB-1989) - track concrete/ATS on earth work – 390 m Waghäusel (DB-1996) Contact :

SATO Gmbh Weststrasse 62 D-08523 Plauen


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II . 6 Family 6 : systems with punctual faste ning of the rail on sleepers separated from supporting structure by a resilient level

This layout family includes reinforced concrete sleepers assuring the inclination and gauge of the two lines of rails simultaneously. The bottom part of sleepers is fit up to receive a boot acting as stiffness on the lateral faces and including a resilient pad on the inferior face . The top/down building method consists, after installation of sleepers and rails and regulating of geometry, to pour in situ an infill concrete between supporting structure and elastic boot. This layout is used mainly in tunnel with a raft playing the role of supporting structure. II . 6 . C : Systems with 2 resilient levels and heavy intermediate.

II . 6 . C . 1 type STEDEF layout


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Variants can exist concerning the set of the concrete, previous realisation of grooves with slipform-paver or system of prior slab for example. A wedging concrete remains nevertheless necessary. References : - test track in tunnel – 210 m Bötzberg (CFF – 1966) - test track on earth work – 72 m Radcliffe (BR/UIC - 1969) - track on earth work – 300 m Neuilly/Marne (SNCF - 1972) - track – 1.6 km Copenhague (DSB – 1974) - track in tunnel –10 km Heitersberg (CFF – 1975) - track in tunnel – 7.5 km Aulnay+Corbeil (SNCF – 1975) - test track on bridge –74 m Avignon (SNCF – 1978) - track various in tunnel – 12 km m (SNCF – 1979/1985) - track in tunnel– 9.2 km RER C Paris (SNCF – 1988) - track – 15.9 km Zürich (CFF – 1979/1990) - track in station – 840 m Malaga (RENFE – 1983) - track various – 55 km (RENFE – 1984 à 1994) - track in tunnel –11.5 km Grauholz (CFF – 1995) - track TGV in tunnel - 8.5 km interconnexion (SNCF – 1996) - track in tunnel –14 km Passante di Milano (FS – 1997) - track in tunnel – 8.7 km RER E Paris(SNCF – 1999) Contact :

SNCF / IGEVT 144 rue des Poissonniers F- 75876 Paris Cedex 18

RAILTECH STEDEF Zone industrielle du Bas Pré – B.P. 9 F- 59590 Raismes

COOPSETTE VIA BIAGIO, 75 I – 42024 CASTELNOVO SOTTO


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II . 6 . C . 2 SATEBA S312 layout This evolution of the STEDEF layout brings two improvements: - to make possible a repair, following derailment or material damage, while limiting intervention to the replacement of the sleeper without necessity to make again the wedging concrete; - to make waterproof the assembling of the sleeper in the layout. These objectives are reached by the following way: - manufacture of the sleeper with reduced dimensional tolerances; - use of a rigid hull instead of a rubber boot in order to create a print in the wedging concrete with reduced dimensional tolerances; - lateral stiffness preserved by the elastic pads in the hull and flexible waterproof seal between the hull and the sleeper.

References : - HS track in tunnel – 16 km Marseille (SNCF - 2000) Contact :

SATEBA 262 Boulevard Saint-Germain F- 75007 Paris


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II . 7 Family 7 : systems with punctual fastening of the rail on prefabricated slabs

This layout family includes reinforced or prestressed concrete slabs assuring the inclination and gauge of the two lines of rails simultaneously. The prefabricated slabs include during manufacturing the interfacing with fastening systems. The top/down method of construction consists in adjusting geometrically the slabs over the supporting structure, then to pour between slabs and supporting structure a half-rigid product type bituminous mortar with a 3 to 7 cm thickness. Thus the bringing of wedging material put in situ is reduced , what can present advantages of realisation (requirement of prefabricating a large proportion of the work off-site and independently of site conditions and processes). This bituminous mortar being half-rigid permits to break away rather easily the slabs from the support. Consequently slabs can be considered as replaceable elements and repairs by adjusting the level of slabs are foreseeable. On the other hand the half-rigid character of the bituminous mortar can cause concerns on its life span and the tendency to the beating of slab ends. The property of resilient level of the bituminous mortar can lend to discussion following its thickness and its composition. Two sub-families can be considered. For the first one (7.B) the final assembly can be seen as a monolithic layout and it is recommended to have a mechanical link between slabs. For the second sub-family (7.C) the separation layer is seen as resilient, even if its contribution to global stiffness of track is rather low (the main part of global stiffness is brought by fastening system). Then the resilience of bituminous mortar permits independent behaviour of the supporting structure and of the slabs. On the other hand solutions must be found for the transmission of horizontal efforts, generally by mean of an upstand in supporting structure and relevant opening in slabs.


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II . 7 . B . 1 type BÖGL layout

This system includes slabs of 6.45 m x 2.5 m (or 2.8 m) x 0.20 m with a two resilient level fastening system (type IOARV300 or Krupp ECF). As the fastening system is doubly elastic , the wedging mortar under slabs doesn't constitute a resilient level necessary and its thickness can be reduced to 3 cm. Slabs are mechanically linked (welded bars earlier). References : - test track on earth work– 430 m Dachau-Karlsfeld (DB- 1977) - track on earth work – 657 m in station Rot-Malsch (DB- 1999) - track in curve on earth work – 214 m Hattstedt (DB- 1999) Contact :

MAX BÖGL P.O. Box 1120 D- 92301 Neumarkt


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II . 7 . C : Systems with 2 resilient levels and heavy intermediate. II . 7 . C . 1 Japanese layouts with prefabricated slabs

The Japanese railroads (JNR / RTRI) developed several variants of systems with prefabricated slabs using prestressed or reinforced concrete slabs of about 5 m x 2.34 m with a 0.16 or 0.19 m thickness. These slabs include an adjustable fastening system with a single resilient level, the complementary stiffness being brought by a bituminous mortar of minimal 4 cm thickness and possibly a rubber mat in some antivibrating versions. These slabs are generally stopped with a resilient link on circular upstands of supporting structure.


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The recent evolutions includes slabs with hollows in middle to optimise the setting up of the bituminous mortar.

Japanese grant an special attention to the bituminous mortar either for the supplying and setting costs or for its technical performances. Two composition types exist according to the meteorological conditions of the site of use and the bituminous mortar (CAM: cement asphalt mortar) includes 9 elementary components.

References : - Shinkansen tracks (Japan) : Ballastless track Earth length works Sanyo (1975) Osaka - Hakata 4 Tohoku (1982) Tokyo - Morioka 24 Joetsu (1982) Omiya - Niigata 2 Hokuriku (1997) Takasaki - Nagano 19 Contact :

bridges

tunnels

59 313 148 35

218 114 106 63

Total ballastless 281km 451 km 256 km 117 km

Railway Technical Research Institute Track Technology Development Division 2-8-38 Hikari-Cho, Kokubunji City Tokyo 185-8540 JAPAN


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II . 7 . C . 2 type ÖBB-PORR layout This system includes slabs of 5.16 m x 2.4 m x 0.16 to 0.24 m with a two resilient level fastening system type IOARV300. Slabs present two central rectangular openings of 0.91 m x 0.64 m to facilitate the setting up of the wedging mortar and to transmit horizontal efforts.

The separation of polyurethane-cement onIn thethe bottom (3 mm slab thickincludes with C =a resilient 0.5 N/mm3) and onlayer the side faces of the openings. same surface operation of the wedging mortar, a concrete plug is made at the opening with a conical shape to prevent uplift. In its standard design, this is a mass-and-spring system with a mass of 1 tonne per linear meter with advantages against vibrations.


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References : - test track on earth work – 450 m langenlebarn (ÖBB - 1989) - track in tunnel – 4296 m Tauerntunnel (ÖBB - 1991) - test track on bridge – 52 m Helwagbrücke (ÖBB - 1993) - track in tunnel – 11000 m Galgenbergtunnel (ÖBB - 1997) - track in tunnel – 650 m Römerbergtunnel (ÖBB - 1997) - track in tunnel – 4700 m Zammer tunnel (ÖBB - 1999) - track in tunnel and on bridge – 11000 m Kaponig + Ochenig (ÖBB - 1999) - track in tunnel – 3730 m Wolfsgrubentunnel (ÖBB - 2000) - track in tunnel and on bridge – 8570 m Wachberg + Melker (ÖBB - 2000) - track in tunnel – 12950 m Siebergtunnel (ÖBB - 2001) - track – 6000 m Lehrter bahnhof (Ost-West verbindung) (DB - 2002) - track – 3250 m S7/rennweg Flughafenschnellbahn (ÖBB - 2002) Contact :

PORR TECHNOBAU Absbergasse 47 A - 1103 WIEN

ÖBB Infrastruktur – Fahrweg Technik Hegelgasse 7 A – 1010 WIEN

II . 7 . C . 3 type IPA layout This system includes slabs of 4.15 m x 2.5 m x 0.18 m with a two levels plated fastening system. Slabs present two protuberances (0.18 + 0.17 m) at ends to anchor in supporting structure. Slabs are wedged with a bituminous mortar of 5 cm thickness. References : - test track in station – 60 m Gorlago (FS- 1984) - track in tunnel+bridges+earth work – 57 km Udine-Tarvisio (FS- 1986+1988) - track in tunnel – 5 km Caanizzaro (FS- 1988) - track on bridges – 5 km Fiumicino aeroporto (FS- 1988) - HS track in tunnel and on bridges – 5 km Roma-Firenze (FS- 1991) - track en tunnel – 26 km Verona-Brennero (FS- 1993) Contact :

INDUSTRIA PREFABRICATI E AFFINI Via Provinciale Per Tresore I- 24050 CALCINATE (BG)


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Project : Feasibility study « ballastless track »

Third part : Potential studies about ballastless track

It iscomplete proposedthe to continue works studythe by development following twoofaxes : the first aims to state of the art for andthe thefeasibility second aims specifications to allow the railways to define requirements applicable to projects with ballastless track.

III . 1 Works to complete the state of the art of ballastless tracks III . 1 . 1 Enrichment of the state of the art

Everybody writes papers in respected Railroad magazines about the construction of ballastless track, but after the construction story it is never communicated whether the promised advantages are realised and which unexpected properties or behaviour has been discovered. Then it is also proposed in the future studies to make an investigation after a number of ballastless types of track which are presented by railroad companies as proven systems. This investigation should content the year of installation, the track load, the present condition of the track, the maintenance which has been carried out and the required maintenance. The investigation has to be very comprehensive, which means that the workgroup who has to do this job must consist of people with an extensive practical experience in this field. In principle only (maintenance) information from railroad companies should be accepted. Information from manufacturers however must be either rejected or at least checked very conscientious. This job is likely a necessary intermediate step before general guidance for the choice of ballastless track desired by infrastructure managers.

It is proposed to create a steering group for the future studies including few track experts from railway companies to steer the proposed studies. It doesn’t seem appropriate to give this study to bodies like universities or ERRI . The « ballastless track » project group will: - complete the state of the art and help UIC by giving help on the subject ballastless track - organise the studies described in III . 2 and get some data for these studies and validate the studies.


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III . 1 . 2 Economic studies

III . 1 . 2 . 1 Generalities As mentioned previously the cost of construction of a ballastless track is greater than the one of a ballasted track. This extra cost is compensated by a weaker maintenance cost. The economic approach must therefore be made with a survey of the life cycle cost (LCC). However two categories of factors are very badly suitable to the economic calculation: on the one hand track availability costs are with difficult to generalise (the harmonisation of the infrastructure rating is not yet made for the operating companies and even less for the maintenance of the infrastructure); on the other hand choices can be made, as the possibility to change components in case of derailment or the wish to reduce needs in labour, that express social policies or management of risks that can be quoted and generalised with difficulty. If these factors are separated one can however try to approach construction and maintenance costs. Following costs are given only for guidance to have size orders.

III . 1 . 2 . 2 Construction costs In relation to the construction cost of a new line the track only represents 10 to 25% of the total cost of projects. According to the INFRACOST survey of the UIC (support group Management Sector of the Infra commission) the cost of ballasted track (without switches) is 500 € by meter of high speed track, whereas the cost of a ballastless track is 1300 €, so a factor 2.6. This last average factor regains situations very dispersed, from of a factor 1.2 announced by the Japanese for the AF slab track in tunnel, until a maximum of 4 announced by the INFRACOST survey. The deviation of the extra cost factor can be assigned to several reasons: - the distinction to make between the different cases of application (earth works / bridges / tunnels) with the question of the limit between the track and the supporting structures - specificities of each project with labour and supply costs that vary according to countries and to the logistical conditions of each working site - the options chosen by the infrastructure owner especially for the replaceable components, the adjustable fastenings option and equipments against noise and vibrations. The basis ballasted track cost is to modulate according to projects. The layout option of under-ballast mat raises the price of about 40%. In the particular case of tunnels the superior clearing of ballasted track leads to a supplementary section to dig raising the cost of the civil engineering of about 250 €, so 50% of the price of the track.


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The following table gives examples of construction cost for projects without particular difficulties for different tracks on different supports (direct comparisons between examples are not relevant): Costs by track meter Supplies

UIC 60 rails Fastening systems Concrete sleeper Ballast including transport (4.7 t/m) Wedging mortar / concrete (0.6 m3/m - 0.015 plates) Support concrete (1.7 m3/m) Working

Setting and adjustment of the track Pouring of wedging concrete Layout of support concrete with road finisher machine

Standard high speed ballasted track on earth work 52% r f s b

Ballastless Track

Ballastless track

in tunnel

on earth work

r 2.0 (adjustable) to 8.0 (plated) x f

r 2.0 x f

0

0

0 0 33 %

0

0 0

0

Studies and engineering, overhead costs

15 %

15 %

15 %

Total (indicative)

500 € 1.0

1.1 to 1.5

1.3 to 3.0

Overhead

Ratio ballasted track

The ratio to ballasted track depends on many factors like characteristics of alignment or length of tunnel, difficulties of supply of the yard or options for noise or vibrations. In case of tunnel a low cost implies that the design of track is taken in account in the design of the tunnel from the beginning. Low cost for the direct laying on adjustable plates supposes a supporting structure, tunnel raft or bridge deck, accepting anchors for fastening systems. Therefore the cost is to possibly raise for supplementary interfacing layers . On the other hand in the case where a direct fixing without layers of interfacing is admitted on the technical plan on the bridge deck, an economy on the structure of the bridge is foreseeable by reduction of the weight of the track.


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III . 1 . 2 . 3 Maintenance costs Maintenance costs are obviously very variable. Besides the variation of supplying and labour costs according to countries, maintenance costs depend on the one hand on the traffic supported by the track (tonnage and speed) and on the other hand on the objectives followed by the infrastructure manager for the comfort, the reliability and the availability of the line. For a track with a big traffic the current maintenance of the track can be appraised to the following cost by meter of track and per year: Fictive example various Material maintenance inspection

Ballasted track

Ballastless comments track ballast weed killing Including ¾ for switches and crossings punctual replacement of sleepers in ballasted track Reduction for expected lower evolutions

Keeping of track geometry Rail maintenance Total indicative

Cancellation of operations linked to ballast Cutting down of grinding and repair of imprints due to ballast ballastless track economy

The INFRACOST survey points out a factor 2.8 for Japan that otherwise announces 50% of the cost for the single geometry in ballasted track and a reduction of the cost to the ¼ for the slab track. The current maintenance cost can lend to discussion according to the consistence of operations; one will especially keep in mind the economy for ballastless track compared to ballasted track. To the current maintenance cost it is necessary to add renewal costs if one compares with a ballastless track with a claimed life span over 40 years. In a simple feasibility study it does not appear possible to give general indications for costs and consistency of maintenance or regeneration operations allowing to sketch a study on the life cycle cost (LCC). There are too much variations of parameters linked to the project (characteristics of admissible load, alignment and speed, conditions of realisation ) or to the ulterior operation of the line ( supported tonnage, policy of maintenance depending on the reliability and the availability of the infrastructure).


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III . 1 . 2 . 4 Proposal for future studies

On earth works it doesn't seem appropriate that the Civil Engineering support group finances in a first phase an economic survey for the following reasons: - the profitability of a ballastless track is not justifiable only with construction and maintenance costs; the other justifying (availability and politics of maintenance) don't yet make the object of harmonised costs and are responsible to the free choice of the infrastructure owner; - only one network, the DB, has a politics of generalised use of this construction type; thereofarethenoDB meaningful contributions wait from the other -therefore a challenge requirements aiming totoreduce structures to networks; decrease the cost can drive to incur supplementary risk towards questions of heterogeneity and settlement of earth works; therefore one cannot suppose that the factor of construction extra cost may decrease very distinctly below 2; reductions of cost with equal requirement depend on a stake in competition of suppliers which otherwise take patents on the brought improvements. In the same way on railway bridges it doesn't seem appropriate that the Civil Engineering support group finances in a first phase an economic survey for the following reasons: - the lack of common rules on questions of expandable lengths, adjustable or sliding fastenings and separation between structure of bridge and structure of track, bring to the different concepts therefore to very different costs; - the reduction of the construction cost of the structure by reduction of the weight of the track is a controversial question; it probably comes from the absence of a single design for ballastless track; -point everyofrailway with a difficult great length is seen as a particular view ; itbridge is therefore to pull a generality of it. case including the track On the other hand the ballastless track layout in tunnel with raft is experienced by several networks and can make the object of a more detailed economic survey in a first phase. This survey should establish the life cycle cost for four types of solution: monolithic layout, STEDEF type layout, slab track layout and direct layout with plates. Besides while considering extra costs generated to junctions between ballastless track and ballasted track that cannot be treated correctly by tamping, the survey will specify an advisable minimal length for the systematic layout in ballastless track in tunnel.


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III . 2 Elements of requirements

III. 2. 1 Definition of the global stiffness

The necessity to limit the stiffness of the track to reduce the vertical dynamic efforts between wheels and rail is now admitted. Furthermore this requirement is mentioned in the Technical Specifications for Interoperability for high speed. However there is no standard definition of the global stiffness of the track. Therefore this global stiffness prescription takes some various shapes: for example objective of value of rail displacement for a nominal axle load or prescription of means with imposition of a fastening system for example. This situation is regrettable because it calls upon debatable load notions (to see point 2. 2 here after) or because it limits arbitrarily the possible solution range. In ballastless track systems it can be considered that a controlled stiffness is introduced between the rail and a supporting structure (apron of bridge, raft of tunnel, cement stabilised or asphalt layers) rigid relatively to the resilient levels between rail and supporting structure. The fact to control the stiffness permits to limit the scattering of the stiffness compared to ballasted tracks for which variations of supporting structure stiffness strongly influences the global stiffness and the ballast layer stiffness. It seems stiffness include: -

-

possible to remedy the quoted inconveniences previously while elaborating some prescriptions applicable only to the ballastless track. These prescriptions could a global stiffness definition: for example static stiffness at the rail in kN/mm; some rules of transposition of the global stiffness in stiffness specific to each type of ballastless track: for example stiffness in MN/m² by stretch of rail for embedded rail systems or stiffness in kN/mm for systems with plates or a sleeper head according to sleeper spacing; comments or recommendations on the spacing of supports for systems with non continuous support of rails; an objective of stiffness with the method of assessment: for example a dynamic stiffness between 50 and 100 kN/mm for the specific stiffness of plated systems measured according to appendix B of prEN 13481-5; a validation calculation of the load transmitted to the supporting structure: validation of the ½ coefficient of the eurocode prEN 1991-2 for example.


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III . 2 . 2 Definition of loads

A too fast reading of the Technical Specifications for Interoperability for high speed could let believe that it is sufficient to take limit values of wheel loads (according to leaflet UIC 518) to size supporting structures according to the eurocode prEN 1991-2. This way to proceed could drive to mistakes for the following reasons: - the authorised maximal loads of the leaflet UIC 518 are checked while limiting the low-pass frequency band to 20 Hz; therefore they don't include the total solicitations of the track particularly degraded situations of vehicles as wheel flats; - the ballastless track claims a better track geometry therefore lower dynamic overloads; therefore one should separate in the dynamic solicitations overloads bound to the track (quasi-static efforts of the alignment and geometry defects) and those bound to vehicles (swaying efforts, roughness of wheels); - the loads described in the eurocode 1991-2 are adapted to ballasted tracks but not indeed to certain types of ballastless track; for example for plated layout one should take in account guiding efforts (load Y by rail) and not transverse hunting efforts (limit of Prud'homme); the distribution of efforts doesn't follow a diagram of load under ballast but is very dependent on the stiffness as mentioned before. Consequently it seems useful to foresee a survey to elaborate guidelines for the calculation of supporting structure of ballastless track.

The Specifications for Interoperability high speed a dynamic vertical wheelTechnical load of about 170 kN, what allows a dynamicforoverload factorallow of about 2 for high speed axles and a dynamic overload factor of 1.36 for 25 tons axles rolling practically at rather weak speed. The dynamic load of 170 kN (by wheel) could be applied therefore for the normal loads. Towards exceptional loads, taken in account for example for the calculation of the concrete sleeper for ballasted track (impact coefficient k2d in prEN 13230), one should get closer of the structure group experts to examine in what measures the difference between normal dynamic loads and exceptional loads can be compensated by the safety coefficients specific to methods of calculation of the prEN 1991-2. A similar analysis can be driven on the transverse loads while considering the limit of Prud'Homme and the Y/Q < 0.8 criteria quoted by the TSI. Under reserve of a minimum of stiffness standardisation as mentioned in 1. 1, transpositions of wheel loads in loads over supporting structures can then be considered for a calculation type prEN 1991-2 applied to supporting structures. Some tests with measurement of wheel loads (type UIC 518 leaflet) can be considered on ballastless tracks to justify by measurements the dynamic overloads to keep in rules of calculation. These prescriptions should be validated by the structure experts group for the interfacing with prEN 1991-2 and by the Sub Commission 57 B for the definition of loads.


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III . 2 . 3 Specification for adjustable fastenings

It can be thought that it is useful to specify the adjustable fastening utilisation while specifying their domain of use and fixing regulating limits. For the domain of use two utilisations are possible: at the time of the construction and to correct anomalies affecting the support of the track after it is on duty. The use of the fastening regulating for the construction drags some important costs in manpower and in supplying of components; therefore this solution must be avoided. The use of the fastening regulating to correct distortions affecting the support after it is on duty permits to limit consequences of unforeseeable phenomena. It is therefore a supplementary insurance against risks. These risks being quantifiable with difficulty and the proof that they are limited being impossible to bring, it is difficult to justify an amplitude of regulating of fastening systems. More the range of regulating is important and less will be important the necessary speed reduction to compensate the risk at the srcin of the distortion; it is more especially true for a high speed operation. On the other hand it should be possible to define in collaboration with the track experts group a minimal adjustment range allowing to facilitate operations of rail replacement in cases of a ballastless track including rails having already undergone a wear in operation. III . 2 . 4 Experimentation of behaviour laws for ballastless track

The goal of tests is to get a reduced catalogue of behaviour laws for ballastless track systems. One will disregard the deformation of supporting structures to focus only on controlled resilient levels from the point of view of vertical stiffness and longitudinal stiffness. The vertical behaviour is necessary for points 2.1 here before and 2.5.2 here after. The protocol of test will include a static measure with complete behaviour law and a dynamic stiffness according to prEN 13481-5. The longitudinal behaviour is necessary for points 2.5.1 and 2.5.3 here after. The protocol of test will include a static measure of sliding for unloaded track according to prEN 13146-1 with a complete behaviour law interpreted to isolate a stiffness part and a sliding part. It is proposed to make laboratory tests on following systems: 1. embedded rail EDILON 2. plate Pandrol VIPA SP with standard clips (Fastclip) 3. Pandrol VIPAVossloh SP withIOARV reduced300 longitudinal resistance 4. plate fastenings system standard (Skl 15) clips 5. fastenings system Vossloh IOARV 300 with reduced longitudinal resistance (Skl 15 B) 6. STEDEF system or assimilated.


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III . 2 . 5 Survey of CWR / bridge interaction with ballastless track

In this part one intends to make investigating studies about CWR / bridge interaction with ballastless track. Results of this survey will be published in a technical document and will be transmitted to the structures experts group who will appreciate if one should foresee an updating of the leaflet UIC 774-3 to better take in account ballastless track.

III. 2 . 5 . 1 Definition of a criteria for fastenings with a reduced longitudinal resistance for ballastless tracks The use of fastening systems with reduced longitudinal resistance permits to decrease efforts in rails at bridge ends, what permits to increase the expandable lengths without expansion devices for the CWR / bridge interaction. It would agree to formalise a criteria limiting the maximal length of use of fastening of this type according to their sliding characteristic. This criteria would be in relation with the maximal opening of the gap in case of rail breaking. III . 2 . 5 . 2 Investigation of a deformation criteria at bridge ends for ballastless track Deformations of bridge extremities bound to the vertical bending of spans under load result in rotations of extremities and a vertical uplift of overhanging parts beyond bearing. These discontinuities of angle or displacement at the level of supporting structure cannot exist at the level of rails that react while bending by soliciting the link between rail and structure. In ballasted track the ballast layer presents a rather big capacity of deformation until the ability of loose between sleeper and ballast. In ballastless track one should examine consequences on the behaviour of the rail fastening system and its technology. Therefore a simple model of the track will be established with the vertical inertia of the rail and the stiffness between rail and support and one will introduce as loading discontinuities in the support (angle or uplift); then one will examine solicitations in effort and displacement in fastenings. These solicitations will be examined from the point of view of system technology (for example a down load solicitation is accepted without problem by pads but an uprising beyond the toe load can solicit clips directly beyond their elastic domain). This analysis will be done on the examples surveyed in 2.4.


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III . 2 . 5 . 3 Interaction calculations with fastening with reduced longitudinal resistance A study is intended on two examples of bridge configurations to exam effects of CWR / bridge interaction. Results will be analysed from a track point of view while considering that the buckling risk of CWR is not conditioned anymore by a sliding in the ballast. The two foreseen configurations are: . single expandable length of 100 m without expansion device (1 fix bearing at one end) . succession of 8 decks of 100 m without expansion device with central fix bearing (so expandable lengths of 50 m at ends and intermediate expandable lengths of 100 m). The fix bearing stiffness will be the minimum value permitting to respect the displacement of decks under braking according to prEN 1991-2. Longitudinal behaviour laws between rail and support will be shape no linear compliant to results of the point 2.4 . For cases 3 and 5, the maximal length with fastening with reduced resistance will be compliant to the criteria to define in 2.5.1 .


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Ballastless Track

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