What is track?
The track on on a railway or railroad , also known as the permanent way , is the structure consisting of the rails, fasteners, railroad ties (sleepers, ties (sleepers, British English) and ballast (or slab track), plus the underlying subgrade subgrade.. For clarity it is often referred to as railway (British English and UI ter!inology) ter!inology) or railroad track (predo!inantly (predo!inantly in the United track (British "tates). The ter! permanent way also also refers to the track in addition to lineside structures structures such as fences etc
Track structure
The track on a railway railway (non#U") or railroad railroad (U"), also known known as the per!anent per!anent way, way, is the structure consisting of the rails, fasteners, sleepers and ballast (or slab track), plus the underlying subgrade. For clarity it is often referred to as railway track (British English and UI ter!inology) or railroad track (predo!inantly in $orth %!erica).
Traditional Track Structure (Ballasted Track)
"ection through railway track and foundation showing the ballast and for!ation layers. The layers are slightly sloped to help drainage. $otwithstanding $otwithstanding !odern technical de&elop!ents, the o&erwhel!ingly o&erwhel!ingly do!inant track fro! worldwide consists of 'at#botto! steel rails supported on ti!ber or pre#stressed pre#stressed concrete sleepers (referred to as railroad ties in the U"), which are the!sel&es laid on crushed stone ballast. ost railroads with hea&y trac use continuously welded rails supported by sleepers (ties) attached &ia baseplates (tieplates) (tieplates) which spread the load. % plastic or rubber pad is usually placed between the rail and the tieplate where concrete sleepers (ties) are used. The rail is usually held down to the sleeper (tie) with resilient fastenings, although cut spikes are widely used in $orth %!erican practice. For !uch of the *+ th century, rail track used softwood ti!ber ties and ointed rails, and considerable e-tents e-tents of this track type re!ains on secondary and tertiary routes. The rails were typically of 'at botto! section fastened to the
ties with dogspikes through a 'at tieplate in $orth %!erica and %ustralia, and typically of bullhead section carried in cast iron chairs in British and Irish practice. ointed rails were used, at /rst because the technology did not o0er any alternati&e. 1owe&er the intrinsic weaknesses in resisting &ertical loading results in the ballast support beco!ing depressed and a hea&y !aintenance workload is i!posed to pre&ent unacceptable geo!etrical defects at the oints. The oints also re2uired to be lubricated, and wear at the /shplate (oint bar) !ating surfaces needed to be recti/ed by shi!!ing. For this reason, oined track is not /nancially appropriate for hea&ily operated railroads. Ti!ber sleepers (ties) are of !any a&ailable ti!bers, and are often treated with creosote, copper#chro!ic#arsenic, or other wood preser&ati&e. Ti!ber sleepers !ay be of hardwood or softwood, and are custo!arily treated with creosote or other wood preser&ati&e. 3re# stressed concrete sleepers (ties) are often used where ti!ber is scarce and where tonnage or speeds are high. "teel is used in so!e applications. The track#ballast is custo!arily crushed stone, and the purpose of this is to support the ties and allow so!e adust!ent of their position, while allowing free drainage. Ballastless
Ballastless high#speed track in hina % disad&antage of traditional track structure is the hea&y de!and for !aintenance, particularly surfacing (ta!ping) and lining to restore the desired track geo!etry and s!oothness of &ehicle running. 4eakness of the subgrade and drainage de/ciencies also lead to hea&y !aintenance costs. This can be o&erco!e by using balllastless track. In its si!plest for! this consists of a continuous slab of concrete (like a highway structure) with the rails supported directly on its upper surface (using resilient pad). There are a nu!ber of proprietary syste!s, and &ariations include a continuous reinforced concrete slab, or alternati&ely the use pd pre#cast pre#stressed concrete units laid on a base layer. any per!utations of design ha&e been put forward. 1owe&er ballastless track is &ery e-pensi&e in /rst cost, and in the case of e-isting railroads re2uires closure of the route for a so!ewhat long period. Its whole life cost can be lower because of the great reduction in !aintenance re2uire!ent. Ballastless track is usually considered for new &ery high speed or &ery high loading routes. In short e-tensions that re2uire additional strength (e.g. rail station), or for locali5ed replace!ent where there are e-ceptional !aintenance diculties, for e-a!ple in tunnels.
Ladder track
6adder track at %kabane "tation 6adder track utili5es sleepers aligned along the sa!e direction as the rails with rung#like gauge restraining cross !e!bers. Both ballasted and ballastless types e-ist. Continuous longitudinally supported track
Early railways ( c. 789+s) e-peri!ented with continuous bearing railtrack, in which the rail was supported along its length, with e-a!ples including Brunel:s Baulk ;oad on the
hio railway in the 789+s, but was found to be !ore e-pensi&e to !aintain than rail with cross ties. odern applications of continuously supported track include Balfour Betty:s ?E!bedded "lab Track: which uses a rounded rectangular rail pro/le (BB79+@*) e!bedded in a slipfor!ed (or pre#cast) concrete base (de&elop!ent *+++s), the ?E!bedded ;ail "tructure:, used ion $etherlands since 7A@, initially used a con&entional UI C9 rail e!bedded in concrete, later de&eloped (late 7AA+s) to use a ?!ushroo!: shaped "%9* rail pro/leD a &ersion for light rail using a rail supported in an asphalt concrete /lled steel trough has also been de&eloped (*++*).
Track Layout The geo!etry of the tracks is three#di!ensional by nature, but the standards that e-press the speed li!its and other regulations in the areas opf track gauge, align!ent, ele&ation, cur&ature and track surface are usually e-pressed in two separate layouts for hori5ontal and &ertical. 1ori5ontal layout is the track layout on the hori5ontal plane. This in&ol&es the layout of three !ain track types tangent track (straight line), cur&ed track, and track transition cur&e (also called transition spiral or spiral) which connects between a tangent and a cur&ed track. ertical layout is the track layout on the &ertical plane including the concepts such as crossle&el, cant and gradient.
Ballastless track rail trac is reaching out toward new hori5ons on ballastless track syste!s. The argu!ents are indeed con&incing long life cycles, top speed, ride co!fort, and great load#carrying capability. =ou take no chances with these syste!s, especially with newly constructed lines e&en at speeds o&er G++ k!Hh, your co0ee will stay in your cup. 3ractically !aintenance free, ballastless track syste!s ensure al!ost 7++ a&ailability o&er !any years. In !any cases, a !aintenance#free track syste! is indeed the !ore cost# e0ecti&e solution o&er the long run. The actual breakthrough in
PN 3hilippine national railway !ostly use ballasted tracks as a track structure. This is because they keep stones between tracks. The stones placed in and around railway tracks are technically called LballastM. The railway track, na!ed L3er!anent 4ayM in rail lingo, is a !ulti#entity structure which co!prises the pair of rail lines running parallel, the spaced sleepers, the ballast and the for!ation.The force e-erted by the wheels of the train is
trans!itted successi&ely in a proportionally di!inishing e-tent down the rails, the sleepers and the ballast to the for!ation, a well prepared and consolidated road bed. The ballast consists of broken stones of speci/c di!ensions. The stability of the track depends on the depth of the ballast which i!parts a cushioning e0ect to the track. The standard depth of ballast for trunk route is *C c!s ,for the Broad
"tones#
Today, 3$; can only respond in kind by o&erco!ing all the odds of its recent history. a-i!i5ing all its e-isting resources, rehabilitation work is going on full speed ahead especially along its infrastructure. Before train operators can e&en think of replacing or refurbishing the trains or railcars the!sel&es, the tracks, railroad ties, and bedding or e!bank!ent !ust be strengthened or reconditioned to carry the weight of new or repaired rolling stock. ;ight now, to strengthen tracks and bridges, 3$; is replacing the e-isting wooden ties with prestressed concrete sleepers. >ther /r!ing#up !easures include Today, 3$; can only respond in kind by o&erco!ing all the odds of its recent history. a-i!i5ing all its e-isting resources, rehabilitation work is going on full speed ahead especially along its infrastructure. Before train operators can e&en think of replacing or refurbishing the trains or railcars the!sel&es, the tracks, railroad ties, and bedding or e!bank!ent !ust be strengthened or reconditioned to carry the weight of new or repaired rolling stock. ;ight now, to strengthen tracks and bridges, 3$; is replacing the e-isting wooden ties with prestressed concrete sleepers. >ther /r!ing#up !easures include ballasting of the tracks, replace!ent of corroded rails with new ones, widening of e!bank!ent, and reconstruction of da!aged cul&erts. 3$; is also reinforcing its bridges and i!pro&ing the drainage syste!. replace!ent of corroded rails with new ones, widening of e!bank!ent, and reconstruction of da!aged cul&erts. 3$; is also reinforcing its bridges and i!pro&ing the drainage syste!.
