RAILWAY TRACK CRACK DETECTOR Robot
SYNOPSIS
SYNOPSIS: The project relates to the detection of cracks in the railway tracks using IR sensor. According to a possible embodiment, the railway carriage carrying the control equipments is provided with sensor orientated to detect the crack. This project pertains to a process for monitoring the condition of rail on train tracks and more specifically has the object of the identification of defects detected by monitoring equipment on the tracks to be checked to allow maintenance crews to subsequently find these defects. Two medal sensors are fixed in the wheels of the train is used to find out the crack on the rail. Each sensor will produce the signal related position with the rail. If the track is said to be normal on its position when both the sensor gives the constant sensed output. If any one misses their output condition to fail then there is defect on that side. It will inform this by giving alarm. Where sensors and alarm should connected to npn transistor.
CHAPTER – 1 INTRODUCTION There are many reasons why rail tracks crack. In bygone days, it was common for a rail crack to start near the joint between discrete rail segments. Manufacturing defects in rail can cause fissures. Wheel burns can also contribute to rail cracks by changing the metallurgy of a rail. Rails are also more likely to crack when the weather is cold, when the ballast and ties/sleepers aren't providing as much support as they should, and when ground or drainage condition is such that 'pumping' occurs under heavy load. All of these conditions can contribute to a broken rail, and in turn a possible derailment. MANUFACTURING DEFECTS IN RAIL: The quality of rail steel has improved dramatically since the early days of railroading. The trend toward using continuously welded rail (CWR) requires a higher quality rail, due to the cyclic thermal expansion and contraction stresses that a CWR would be required to endure. In addition, rail operations in general have been trending toward higher speed and higher axle-load operation. Under these operating conditions, rail pieces rolled in the 19th century would likely
break at an unacceptable rate. Despite the improved rail quality and rail metallurgy, if impurities find their way into rail steel and are not detected by the quality assurance process, they can cause rail breaks under certain conditions. Recent rail-making processes have also been trending toward a harder rail, requiring less frequent replacements under heavy loads. This has the side-effect of making the rail more brittle, and thus more susceptible to brittle fracture rather than plastic deformation. It is therefore imperative that unintentional impurities in rail be minimized. WHEEL BURN-RELATED RAIL CRACKS: When a locomotive wheel spins without moving the train forward (also known as slipping), the small section of rail directly under the wheel is heated by the forces of friction between the wheel and itself. The wheel rests on an area of rail no larger than a dime in size, so the heating effect is very localized and occurs very quickly. While wheel burn typically does not cause the entire rail section to melt, it does heat the steel to red-hot temperatures. As the locomotive stops slipping and starts moving--or worse still, slips forward by a matter of inches and heats a different piece of rail--the heated spot
cools down very quickly to normal temperature, especially when the weather is cold. This heat-quench process results in annealing of the rail steel and causes substantial changes to its physical property. It can also cause internal stresses to form within the steel structure. As the rail surface cools, it may also become oxidized, or undergo other chemical changes by reacting with impurities that are on the surface of the rail. The net result of this process is that an area of the rail that is more susceptible to crackage is created. WHEEL FLAT-RELATED RAIL CRACKS: If the brakes are dragging or the axle ceases to move on a rail vehicle while the train is in motion, the wheel will be dragged along the head of the rail, causing a 'flat spot' to develop on the wheel surface where it contacts the rail. When the brakes are subsequently released, the wheel will continue to roll around with the flat spot, causing a banging noise with each rotation. This condition is known as wheel out of round. The banging of flat wheels on the rail causes a hammering action that produces higher dynamic forces than a simple passage of
a round wheel. These dynamic forces can exacerbate a weak rail condition and cause a rail crack.
CHAPTER-2 LITERATURE REVIEW LITERATURE SURVEY Railway track: Track-caused derailments are often caused by wide gauge. Proper gauge, the distance between rails, is 56.5 inches (four feet, eightand-a-half inches) on standard gauge track. As tracks wear from train traffic, the rails can develop a wear pattern that is somewhat uneven. Uneven wear in the tracks can result in periodic oscillations in the truck, called 'truck hunting.' Truck hunting can be a contributing cause of derailments. A rail breaks cleanly, it is relatively easy to detect. A track occupancy light will light up in the signal tower indicating that a track circuit has been interrupted. If there is no train in the section, the signaler must investigate. One possible reason is a clean rail break. For detecting the rail break this way, one has to use signal bonds that are welded or pin brazed on the head of the rail. If one uses signal
bonds that are on the web of the rail, one will have a continued track circuit. If a rail is merely cracked or has an internal fissure, the track circuit will not detect it, because a partially-broken rail will continue to conduct electricity. Partial breaks are particularly dangerous because they create the worst kind of weak point in the rail. The rail may then easily break under load--while a train is passing over it--at the point of prior fissure.
ULTIMATE AIM The aim of this project is to find out the cracks developed on the railway tracks, due to continuous use or while manufacturing. This is achieved by installing IR (Infra red) sensor and solar power to the maintenance crew’s wagon.
CHAPTER-3
DESCRIPTION OF EQUIPMENT 3.1 BATTERY: Battery is use for storing the energy produced from the solar power. The battery used is a lead-acid type and has a capacity of 12v; 2.5A.the most inexpensive secondary cell is the lead acid cell and is widely used for commercial purposes. A lead acid cell when ready for use contains two plates immersed in a dilute sulphuric acid (H2SO4) of specific gravity about 1.28.the positive plate (anode) is of Lead –peroxide (PbO2) which has chocolate brown colour and the negative plate (cathode) is lead (Pb) which is of grey colour. When the cell supplies current to a load (discharging), the chemical action that takes place forms lead sulphate (PbSO 4) on both the plates with water being formed in the electrolyte. After a certain amount of energy has been withdrawn from the cell, both plates are transformed into the same material and the specific gravity of the electrolyte (H2so4) is lowerd.the cell is then said to be discharged.
There are several methods to ascertain whether the cell is discharged or not.
To charge the cell, direct current is passed through the cell in the reverse direction to that in which the cell provided current. This reverses the chemical process and again forms a lead peroxide (PbO2) positive plate and a pure lead (Pb) negative plate. At the same time, (H2so4) is formed at the expense of water,restoring the electrolyte (H2so4) to its original condition. The chemical changes that Occur during discharging and recharging of a lead-acid cell
BATTERY CIRCUIT DIAGRAM:
CIRCUIT DIAGRAM DETAILS: In our project we are using secondary type battery. It is rechargeable Type. A battery is one or more electrochemical cells, which store chemical energy and make it available as electric current. There are two types of batteries, primary (disposable) and secondary (rechargeable), both of which convert chemical energy to electrical energy. Primary batteries can only be used once because they use up their chemicals in an irreversible reaction. Secondary batteries can be recharged because the chemical reactions they use are reversible; they are recharged by running a charging current through the battery, but in the opposite direction of the discharge current. Secondary, also called rechargeable batteries can be charged and discharged many times before wearing out. After wearing out some batteries can be recycled. Batteries have gained popularity as they became portable and useful for many purposes. The use of batteries has created many environmental concerns, such as toxic metal pollution. A battery is a device that converts chemical energy directly to electrical energy it
consists of one or more voltaic cells. Each voltaic cell consists of two half cells connected in series by a conductive electrolyte.
One half-cell is the positive electrode, and the other is the negative electrode. The electrodes do not touch each other but are electrically connected by the electrolyte, which can be either solid or liquid. A battery can be simply modeled as a perfect voltage source which has its own resistance, the resulting voltage across the load depends on the ratio of the battery's internal resistance to the resistance of the load.
When the battery is fresh, its internal resistance is low, so the voltage across the load is almost equal to that of the battery's internal voltage source. As the battery runs down and its internal resistance increases, the voltage drop across its internal resistance increases, so the voltage at its terminals decreases, and the battery's ability to deliver power to the load decreases.
3.2 ir sensor: Ir transmitter: PLASTIC INFRARED LIGHT EMITTING DIODE:
SCHEMATIC:
APPLICATIONS: Optical communications Safety equipment
DRAWING FOR IR RECEVER:
3.3. MOTOR: D.C.MOTOR PRINCIPLE: A machine that converts direct current power into mechanical power is known as D.C Motor. Its generation is based on the principle that when a current carrying conductor is placed in a magnetic field, the conductor experiences a mechanical force. The direction if this force is given by Fleming’s left hand rule.
WORKING OF A DC MOTOR: Consider a part of a multipolar dc motor as shown in fig. when the terminals of the motor are connected to an external source of dc supply; (i)
The field magnets are excited developing alternate N and S poles.
(ii)
The armature conductors carry currents. All conductors under N-pole carry currents in one direction while all the conductors under S-pole carry currents in the opposite direction.
Suppose the conductors under N-pole carry currents into the plane of paper and those under S-pole carry current out of the plane of paper as shown in fig. Since each armature conductor is carrying current and is placed in the magnetic field, mechanical force acts on it. Applying Fleming’s left hand rule, it is clear that force on each conductor is tending to rotate the armature in anticlockwise direction. All these forces add together to produce a driving torque which sets the armature rotating. When the conductor moves from one side of the brush to the other, current in the conductor is received and at the
same time it comes under the influence of next pole which is of opposite polarity. Consequently the direction of force on the conductor remains same.
PRINCIPLES OF OPERATION: In any electric motor, operation is based on simple electromagnetism. A current-carrying conductor generates a magnetic field; when this is then placed in an external magnetic field, it will experience a force proportional to the current in the conductor, and to the strength of the external magnetic field. As you are well aware of from playing with magnets as a kid, opposite (North and South) polarities attract, while like polarities (North and North, South and South) repel. The internal configuration of a DC motor is designed to harness the magnetic interaction between a current-carrying conductor and an external magnetic field to generate rotational motion.
Let's start by looking at a simple 2-pole DC electric motor (here red represents a magnet or winding with a "North" polarization, while green represents a magnet or winding with a "South" polarization).
Every DC motor has six basic parts -- axle, rotor (armature), stator, commutator, field magnet(s), and brushes. In most common DC motors, the external magnetic field is produced by high-strength permanent magnets. The stator is the stationary part of the motor -this includes the motor casing, as well as two or more permanent magnet pole pieces. The rotor (together with the axle and attached commutator) rotate with respect to the stator. The rotor consists of windings (generally on a core), the windings being electrically connected to the commutator. The above diagram shows a common motor layout -- with the rotor inside the stator (field) magnets.
The geometry of the brushes, commutator contacts, and rotor windings are such that when power is applied, the polarities of the energized winding and the stator magnet(s) are misaligned, and the rotor will rotate until it is almost aligned with the stator's field magnets. As the rotor reaches alignment, the brushes move to the next commutator contacts, and energize the next winding. Given our example two-pole motor, the rotation reverses the direction of current through the rotor winding, leading to a "flip" of the rotor's magnetic field, driving it to continue rotating. In real life, though, DC motors will always have more than two poles (three is a very common number). In particular, this avoids "dead spots" in the commutator. You can imagine how with our example two-pole motor, if the rotor is exactly at the middle of its rotation (perfectly aligned with the field magnets), it will get "stuck" there. Meanwhile, with a two-pole motor, there is a moment where the commutator shorts out the power supply. This would be bad for the power supply, waste energy, and damage motor components as well. Yet another disadvantage of such a simple motor is that it would exhibit a high amount of torque "ripple" (the amount of torque it could produce is cyclic with the position of the rotor).
So since most small DC motors are of a three-pole design, let's tinker with the workings of one via an interactive animation (JavaScript required):
A few things from this -- namely, one pole is fully energized at a time (but two others are "partially" energized). As each brush transitions from one commutator contact to the next, one coil's field will rapidly collapse, as the next coil's field will rapidly charge up (this occurs within a few microsecond). We'll see more about the effects of this later, but in the meantime you can see that this is a direct result of the coil windings' series wiring:
There's probably no better way to see how an average DC motor is put together, than by just opening one up. Unfortunately this is
tedious work, as well as requiring the destruction of a perfectly good motor. The guts of a disassembled Mabuchi FF-030-PN motor (the same model that Solarbotics sells) are available for (on 10 lines / cm graph paper). This is a basic 3-pole DC motor, with 2 brushes and three commutator contacts. The use of an iron core armature (as in the Mabuchi, above) is quite common, and has a number of advantages. First off, the iron core provides a strong, rigid support for the windings -- a particularly important consideration for high-torque motors. The core also conducts heat away from the rotor windings, allowing the motor to be driven harder than might otherwise be the case. Iron core construction is also relatively inexpensive compared with other construction types. But iron core construction also has several disadvantages. The iron armature has a relatively high inertia which limits motor acceleration. This construction also results in high winding inductances which limit brush and commutator life. In small motors, an alternative design is often used which features a 'coreless' armature winding. This design depends upon the coil wire
itself for structural integrity. As a result, the armature is hollow, and the permanent magnet can be mounted inside the rotor coil. Coreless DC motors have much lower armature inductance than ironcore motors of comparable size, extending brush and commutator life.
The coreless design also allows manufacturers to build smaller motors; meanwhile, due to the lack of iron in their rotors, coreless motors are somewhat prone to overheating. As a result, this design is generally used just in small, low-power motors. Beamers will most often see coreless DC motors in the form of pager motors. Again, disassembling a coreless motor can be instructive -- in this case, my hapless victim was a cheap pager vibrator motor. The guts
of this disassembled motor are available (on 10 lines / cm graph paper). This is (or more accurately, was) a 3-pole coreless DC motor.
3.4. GEAR: The gear is made out of nylon. The gears used in this project are spur gears. Spur gears are the simplest and most common type of gear. Their general form is a cylinder or disk. The teeth project radially, and with these "straight-cut gears", the leading edges of the teeth are aligned parallel to the axis of rotation. These gears can only mesh correctly if they are fitted to parallel axles WHEEL AND PINION: Whenever two toothed wheels are in mesh. The large wheel is called as the gear and the smaller one as the pinion, regardless of which one is the driver. GEAR MATERIAL: Numerous nonferrous alloys, cast irons, powder-metallurgy and even plastics are used in the manufacture of gears. However steels are most commonly used because of their high strength to weight ratio and low cost. Plastic is commonly used where cost or weight is a
concern. A properly designed plastic gear can replace steel in many cases; It often has desirable properties. They can tolerate dirt, low speed meshing, and "skipping" quite well. Manufacturers have employed plastic to make consumer items affordable. This includes copy machines, optical storage devices, VCRs, cheap dynamos, consumer audio equipment, servo motors, and printers.
3.5 RAILWAY TRACK: Rail tracks are used on railways (or railroads), which, together with railroad switches (or points), guide trains without the need for steering. Tracks consist of two parallel steel rails, which are laid upon sleepers (or cross ties) that are embedded in ballast to form the railroad track. The rail is fastened to the ties with rail spikes, lag screws or clips such as Pandrol clips. The type of fastener depends partly on the type of sleeper, with spikes being used on wooden sleepers, and clips being used more on concrete sleepers. Usually, a base plate tie plate is used between the rail and wooden sleepers, to spread the load of the rail over a larger area of the sleeper. Sometimes spikes are driven through a hole in the base
plate to hold the rail, while at other times the base plates are spiked or screwed to the sleeper and the rails clipped to the base plate. Steel rails can carry heavier loads than any other material. Railroad ties spread the load from the rails over the ground and also serve to hold the rails a fixed distance apart (called the gauge.) Rail tracks are normally laid on a bed of coarse stone chippings known as ballast, which combines resilience, some amount of flexibility, and good drainage. Steel rails can also be laid onto a concrete slab (a slab track). Across bridges, track is often laid on ties across longitudinal timbers
CHAPTER-IV
EQUIPMENT USED 4.1 COMPONENTS AND ITS SPECIFICATION The railway track crack detector consists of the following components to full fill the requirements of complete operation of the machine. 1. Track 2. Battery 3. Control unit
4. Motor 5. Gears
Chapter -6
WORKING PRINCIPLE CHAPTER-V WORKING PRINCIPLE In this project we are using the sensor to find out the crack in the track; this will be useful for the production of track and Track maintenance. Track needs regular maintenance to remain in good order, especially when high-speed trains are involved. Inadequate maintenance may lead to a "slow order" being imposed to avoid accidents Track maintenance was at one time hard manual labour, requiring teams of labourers who used levers to force rails back into place on steep turns, correcting the gradual shifting caused by the centripetal force of passing trains. Currently, maintenance is facilitated by a variety of specialized machines.
In our project we are using the machine with the help of sensor used to find the crack in the track. The sensor is placed in the front of the front wheel and the controlled by the control unit. When the moving of the rear wheel with the help of motor with the gear arrangement the total model is move on that time the sensor send the signal to the control unit where the crack is in the track are not.
CHAPTER -6
MERITS MERITS
Low cost Reliable Compact in size
CHAPTER-7 APPLICATIONS
It is applicable in the production industries and the track maintenance
CHAPTER-XI CONCLUSION The project carried out by us made an impressing task in the field of railway department. It is very useful for the workers work in the production of track. This project will reduce the cost involved in the concern. Project has been designed to perform the entire requirement task at the shortest time available.
BIBLIOGRAPHY 1. Design data book
-P.S.G.Tech.
2. Machine tool design handbook –Central machine tool Institute, Bangalore. 3. Strength of Materials
-R.S.Kurmi
