Railway Work Shop
INDEX 1. Acknowledgement 2. Introduction 3.
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Layout of Railway Workshop 4. Salient Features of Jodhpur Railway Workshop 5. B. T. C. 6. Shop Organization 7. Machine Shop 8. Mill Wright Shop 9. Black Smith & Heat Treatment Shop 10. Roller Bearing 11. Corrosion Shop 12. Brake Gearing Shop 13. Lifting Shop 14. Project ACKNOWLEDGEMENT To make any endeavor successful, especially where the cooperation so many is needed, a lot of help is needed from those who are in a position to help.
In the Engineering field only theoretical knowledge cannot satisfy an Engineer’s need and only on the basis an Engineer cannot do field work efficiently therefore it is very important for an Engineering student to opt some training. To get this knowledge every student of engineer college takes training according to his own branch in a well established factory or an organization in which work is being done practical and how practical work is managed in normal working condition. I am grateful to MR. RAJAT BHAGWAT, the Training and placement officer, M. B. M. Engineering College, Jodhpur for giving me the permission fro training.
I would like to take this opportunity to thank all those who made my training at NORTH WESTERN RAILWAY WORKSHOP, (JODHPUR) not only possible, but also a learning experience. My sincere thanks to the Sh. Mr. B. C. Soni (B. T. C. Chief Instructor), Mr. M. S. Solanki (Sr. Instructor), Mr. R. K. Jain (Sr. Instructor), Mr. A. K. Gautam (Sr. Instructor), Mr. Rajesh Purohit (Sr. Instructor), Mr. Premdas Vaishnav (Sec. Engineer), Mr. Rajendra (Ju. Engineer), Mr. L. P. Verma (Sr. Sec. Engineer), Mr. Rajendra Sisodia (Store Clerk), Smt. Urmila Solanki (Office Clerk) I also express my sincere thanks to the incharge of B.
T. C. for their regular Guidance and their helpful nature without which I cannot complete my training. I am also thankful to all the incharge of Jodhpur Railway Workshop and their sub ordinates and workers, which helped us a lot and shown the interest in us, it gives me a great pleasure in presenting my training report on Jodhpur Railway Workshop. Sumita Hemrom B. E. II Year Student Mechanical Engineering M. B. M. Engg. College, Jodhpur ADMINISTRATIVE HIERACHY
Jodhpur workshop is handled by Chief Workshop Manager. He is assisted by a team of officers with the sectional staff as under: C. W. M. Sh. S. D. Meena Dy. C. M. E. Sh. D. S. Bhati W. M. Sh. J. P. Sharma W. E. E. Sh. R. S. Choudhary S. P. O Sh. N. S. Chawada S. A. F. A. Sh. K. C. Ramdeo X. En. Sh. D. R. Choudhary A. W. M. Sh. R. A. Yadav W. A. E. E. Sh. L. D. Gautam A. F. A. Sh. S. S. Ram INTRODUCTION Workshop is located near main Railway station of Jodhpur. This workshop is well established and running successfully as a complete organization.
In 1969, to increase administrative efficiency, the post of “Works Manager” was upgraded to Deputy Chief Mechanical Engineer. Now a days, this workshop has not only stopped importing valuable and costly components but also started the production of some essential and sophisticate components. Along with this, the basic role of Jodhpur workshop is: – 1. Periodic over hauling of the Railway coach and bogies at the level. 2. Manufacture and repairing of components used in Diesel engine for Diesel shed. 3. Maintenance and repairing of all the machines, which are installed in Jodhpur Railway station. 4.
Now a days, it is also engaged in production of some components, which needs to be replaced in Railway coaches and bogies. There are 16 regional head quarters in India which are as follows:- 1. Western Railway – Mumbai 2. Central Railway – Mumbai 3. Northern Railway – New Delhi 4. Southern Railway – Chennai 5. Eastern Railway – Chennai 6. South Eastern Railway – Calcutta 7. North Eastern Railway – Gorakhpur 8. South Central Railway – Secundarabad 9. North East Frontier Railway – Guwahati 10. East Central Railway – Hazipur 11. North Central Railway – Allahabad 12. North Western Railway – Jaipur 13. West Central Railway – Jabalpur 4. South Western Railway – Hubli 15. South East Central Railway – Bilaspur 16. East Coast Railway – Bhuvaneshwer SALIENT FEATURES OF JODHPUR RAILWAY WORKSHOP | 1. |Total Area | 115339 sq. m. | | 2. |Covered Area (Shed + Buildings) | 48983 sq. m. | | 3. |Track length | 8820. 9 m. | | 4. |Road Length | 1564 m. | | 5. Electric Consumption | 2. 2 lac units/month | | 6. |No. Of Machines | 446 | | 7. |Standby Generation Capacity | 796 KW | | 8. |Power Demand | 1240 KVA | | 9. |Power Factor | 0. 85 | | 10. Water Storage: Underground | 3337 lit. | | |Overhead |225 lit. | | 11. | Pneumatic Power By | 10 Compressors | POWER SUPPLY The electricity is supplied by JVVNL and is also generated by generator sets in case of supply failure. The requirement of electricity in workshop is as follows:- | 1. |Connected Load | 4600 KVA | | 2. Demand | 1360 KVA | | 3. |Maximum Demand | 1400 KVA | | 4. |Actual Utilization: Day Shift | 110-1250 KVA | | |Night Shift |400-500 KVA | | 5. |Average Consumption per day | 9000 Units | | 6. Lighting Consumption Per Month | 15000 Units | Today the staff strength stands at 2400 employees including 150 supervisors and 6 administrative officers. In 1992 it achieved the ISO 9001 certificate. Shop Organization [pic] BLACK SMITH AND HEAT TREATMENT INTRODUCTION Smithing is understood to handle relative small jobs only such as can be heated in an open fire or hearth. The shop in which the work is carried out is known as smithy’s or smithy shop and various operation are performed by means of hand hammer or small power hammers.
Forging refers to production of those parts which must be heated in a close furnace. The portion of work in which forging is done is termed as the forge and work is mainly performed by means of heavy hammers, forging machines and presses. Shaping of metal is done either by steady compression or by impact between hammer and anvil after heating it above recrystallisation temperature in forging. Forging can be defined as the controlled plastic deformation of metal at elevated temperature in to a predetermined sizes and shapes using compressive forces exerted through some type of die by a hammer, a press or an upsetting machine.
The B. S. H. T. shop is divided as:- 1. Draw gear section 2. Buffer section 3. Spring section INSTALLATIONS 1. Pneumatic power hammers (5 nos. ) 250 kg. Capacity-2nos. 500 kg. Capacity-1nos. 1000 kg. Capacity-2nos. 2. Hydraulic presses (3 nos) 3. Combined shearing, punching and nibbing machine (1 nos) 4. Spring testing machine (2 nos. ) 5. Air blowers (2 nos. ) 50 h. p. 6. Grinder (1 nos. ) 7. Circular saw (1 nos) 8. Power hacksaw (1 nos ) 9. Furnace (6 nos) 10. Shot peening machine (1 nos) 11. Tension (proof load ) testing machine (1 nos) PNEUMATIC POWER HAMMER:-
The hammer has two cylinders compressor cylinder & ram cylinder. Piston of compressor cylinder compresses air and delivers it to the ram cylinder where it accelerate the piston, which is integral with ram delivering the blows to the work. The reciprocation of the compression piston is obtained from a crank drive which is powered from a motor through reducing gear. The air distributor device between the two cylinders consist of rotary valves with parts through which air passes into the ram cylinder, blows & above the piston, alternatively. This drives the ram up & down respectively. HYDRAULIC POWER PRESS:-
In power press the ram is driven by power instead of hand as in the case of hand press , The principal of a typical forging press is as follows:- The fluid passes first from a large capacity tank to a pump and then is delivered on the press with the aid of an accumulator and distributor at a pressure of at a pressure of at 200 to 300 kg/cm. The accumulator fluid pressure flows into to main cylinder and pressure on the top of the large piston. Since the cross-section area of the piston in the main cylinder is large, the press ram is forced down upon the material to be forged which lies on the anvil with high total power.
Each power stroke the large piston is returned into its initial position by action of the working fluid on the piston rod in the pull back cylinder. To perform this motion, a relatively lower fluid pressure, but a large volume of water per unit time is required to accelerate the return stroke. FURNACES: The job is heated to correct forging temperature in a hearth or furnaces. The gas and oil are economical, easily controlled and most widely used fuels. In workshop, we used coal and crude oil as fuel forge furnaces are built so as to ensure a temperature up to 1350 degree centigrade in their working chamber.
Two types of furnaces are used in this shop:- 1. Coke fired furnaces 2. Coal fired furnaces In cock furnace coke is used as fuel. In oil fired furnaces diesel is used as fuel. Diesel is sent by cast iron pipes from diesel tank in an injector and compressed air is sent on high intensity by a blower. The air jet mixed with diesel is used as fuel in oil fired furnace. Furnace are used to red hot the raw material to the required temperature. Fuel is injected into these furnace with a great pressure associated with air blast. This high pressure is generated by centrifugal air compressor, which is situated in the shop itself.
This compressed air from the compressor is then taken to several furnaces through the underground pipes. One man is present near the furnace that puts the raw material and takes out the red-hot material, which is then placed under power hammer. After acquiring the required shape, these products are either hardened by various hardening procedures or simply cooled to the atmospheric temperature. Draw Gear Section:- The draw gear and screw coupling are used to connect two coaches to each other. These are designed for a proof load of 75tones and breaking load of 130t.
The components are specially heat treated to achieve the load bearing capacity. In maintenance procedure of draw gear and screw coupling stress relieving is done. The components made of st 60-61 are to be stress relived and the new material introduced for draw gear IS: 5517-93 Grade35Mn6M03 is not to be heat treated. The maximum temperature up to which draw gear can be heated is 550 C. Buffer Section:- Buffers are used to absorb the shock during impact action of coaches. Apart from absorb the impact energy it also guide the coaches to align in track during turn on curvature.
Each buffer has capacity of 1030 kg-m with a total stroke of 127 mm. Rubber springs are used in this buffer assembly so it have low absorption capacity in earlier part of the stroke which rises rapidly towards the end resulting in absorption of high shock loads and transmitting of minimum end pressure to under frame. Components of buffer assembly: ? Buffer casing (cast steel) ? Buffer plunger (cast steel, forged) ? Rubber buffer pads ? Buffer spindle ? Destruction tube ? Recoil spring ? Recoil spring parting plate ? Buffing spring parting plate ? Recoil spring washer ? Face plate for buffer plunger M-24 Hex head bolt Spring Section:- The springs are used in the bogie for the suspension system of coaches. There are two types of suspension as primary and secondary suspension. The springs classified to primary and secondary system by the load carried by them. Fig: Inspection procedure:- Inspect all components visually for dimensional distortion and surface defects such as cracks, wear, dent marks and pitting etc. Remove scale, rust, light cracks by grinder. Stress relieving. In case of doubt of cracks dye penetration or magna flux machine is used to check the cracks
Load test is done on load testing machine for 100t to 150t. In all this procedure if component is find ok then it is dispatched to the assembly. ROLLER BEARING In passenger coaches of Indian Railway system, only single bearing type axle box arrangement is used, means only two bearing are used to support the axle. The bearing used for this purpose is of Spherical Type Roller Bearing. CONSTRUCTION:- Spherical roller bearing consist of an outer ring having a spherical race way within which two rows of barrel shaped rollers operate. These rollers are guided by an inner ring with two raceway separated by a center rib.
This bearing has self alignment. Spherical roller bearings have a large capacity for radial loads, axle loads in either direction. Spherical roller bearing no. 22336/c3 with 130 mm parallel bore on the inner ring are being used on ICF type coaches. They are directly shrunk fit on the axle journals. These roller bearings are to be inspected periodically as per schedule. Fig: TOOLS AND PLANTS FOR MAINTENANCE OF ROLLER BEARING:- |S. no. |Function |Equipment used | |1. Cleaning of roller bearing |3 stage cleaning plant or pre wash, wash & water rinsing | |2. |Dismounting of spherical roller bearings |Hydraulic dismounting equipment-withdrawal nut | |3. |Mounting of roller bearings |Induction heater with demagnetizing device | |4. |Securing of end locking bolts |Torque wrench | |5. |Visual inspection of demounted roller bearings |Magnifying glass with light | |6. Checking of radial clearance |Long feeler gauge | |7. |Measurement of journal |Outside micrometer | | | | | | | | | DISMOUNTING OF BEARING:- ? For dismounting of bearings, special hydraulic dismounting equipment is used.
This machine injects oil between the journal and bore to the inner ring with high pressure which expands inner ring resulting in breaking of interference. The bearing becomes loose on the journal and slides over it. The bearing is then removed from the journal and sent to the cleaning plant. ? All components of bearing such as inner ring, outer ring, rollers, and cage are examined for cracks, damage and breakage. If bearing is found free from all the defects mentioned above, the radial clearance is measured with feeler gauge. Radial clearance is not within prescribed limits, the bearing is rejected.
RECOMMENDED RADIAL CLEARANCE LIMITS FOR BEARING IN DISMOUNTED CONDITION: |Bearing make |Radial clearance | |SKF |0. 105 to 0. 296 mm | |NBC |0. 080 to 0. 190 mm | MOUNTING OF BEARING:- ? Before mounting the bearings, it is checked that journal and shoulder diameters are within permissible limits. All direct mounted spherical roller bearing have interference fit with axle journal, therefore it requires heating and shrinkage fitting. Heating of bearings is done by using an induction heater. Fig: ? Temperature range for heating the bearing is 100 to 120 centigrade. ? Induction heating is a quick, safe, energy saving and environment friendly process. In this system, bearing is short circuited to perform as a secondary winding whereas the core winding is at primary side. Bearing is placed around a yoke. Due to principal of induction current, bearing is heated due to its electrical resistance and attains the desired temperature. It is recommended to set the machine in such a way that it takes 5 to 7 minutes to attain the temperature of 120c maximum of bearing. ? Heated bearing mounted on journal with the help of hook and it is positioned by giving light taps with plastic hammer. BEARING IS REJECTED FOR THE FOLLOWING DEFECTS: ? Pitted or flaked roller tracks and rollers. ? Cracked or deformed or badly worn out cage ? Cracked inner or outer ring ? Scored or damaged outer surface of the outer ring. ? Indentation or rings or rollers ? Scoring of roller tracks or rollers ? Corrosion damage Excessive or less radial clearance CORROSION SHOP ICF coaches incorporate a no. of pressed steel sections made of thin sheets (1. 6, 2. 0, 2. 5, & 4 mm) and plates of thickness 5 to 16 mm in the construction of the shell. These sheets are considerably stressed as the design of the coaches is based on the principle of a self supporting structure and it is essential that these coaches are maintained in good condition free from corrosion. Corrosion is take place when a steel surface comes in contact with moisture. For prevention the corrosion, film of paint is coated on steel surfaces.
In addition to it, application of an inhibite Zinc Chromate Red Oxide Primer is done to prevent the surfaces coming in contact with atmosphere. Surfaces which are not finish painted have also been given ? coats of bituminous emulsion which gives added protection to the steel surfaces by excluding moisture along with primer. If due to some reason like abrasive action of sand, the bituminous film brake down, the inhibitive primer acts as a second line of defence. Corrosion of steel surfaces starts only when both the bituminous and the primer suffer mechanical injury.
Corrosion is indicated by: ? Flaking of paints ? Flaking of metals ? Pitting and rusting Corrosion can be classified into two categories as vulnerable and not vulnerable. Vulnerable corrosion of parts means, the parts are fully corroded and they should be changed for further operation. The examples of vulnerable members in coaches are tubular frame below lavoratories, trough floor in bays, sole bar, body pillars etc. Not vulnerable parts mean the parts which are corroded to little depth and they may be use still by treatment of corrosion.
The examples of mot vulnerable members are head stock inner and outer along with stiffening tubes, roof sheets, body side doors, partition walls, water tank ceiling construction, battery box etc. All the components of coaches are examined in following way for corrosion:- ? Visual inspection ? By spiked hammer ? In the inner surfaces by making g the holes in corresponding component. ? If the components are corroded excess as prescribed limit then change the component by new one. ? And if the component is not so much corroded then repair the component by scrapping old coats of paint and make new coats of paints of anticorrosive layer
BRAKE GEAR SHOP Presently coaches are mounted with air brake system instead of vacuum brake system due to better braking application. The air brake used is TWIN PIPE GRADUATED RELEASE AIR BRAKE SUSTEM. In this system two pipes known as feed pipe and brake pipe are used, instead of that there are two brake cylinder on each bogie, one auxiliary reservoir, a distribution valve, a control reservoir etc. The air brake system uses compressed air supplied by the main reservoir in locomotive. The locomotive compressors charge the feed pipe throughout the length of the train .
The feed pipe is connected to the auxiliary reservoir and the brake pipe is connected to the brake cylinder through the distributor valve. Brake application takes place by dropping the pressure in the brake pipe. Charging the brake system • Brake pipe throughout the length of train is charged with compressed air at 5 kg/cm2 • Feed Pipe throughout the length of train is charged with compressed air at 6 kg/cm2 • Control reservoir is charged to 5 kg/cm2 • Auxiliary reservoir is charged to 6 kg/cm2 Brake application stage For brake application the brake pipe pressure is dropped by ventilating air from the driver’s brake valve.
Subsequently the following actions take place • The control reservoir is disconnected from the brake pipe. • The distributor valve connects the auxiliary reservoir to the brake cylinder and the brake cylinder piston is pushed outwards for applications of brakes. • The auxiliary reservoir is however continuously from feed pipe at 6kg/cm2 |Description |Reduction in B. P Pressure | |Minimum Brake application |0. 5 to 0. kg/cm2 | |Service Brake application |0. 8 to 1. 0 kg/cm2 | |Full service Brake application |1. 0 to 1. 5 kg/cm2 | |Emergency Brake application |Brake pipe is fully exhausted and its pressure reduces | | |to almost zero. | Brake release stage: Brakes are released by recharging brake pipe to 5 kg/cm2 pressure through the driver’s brake valve. ? The distributor valve isolated the brake cylinder from the auxiliary reservoirs. ? The brake cylinder pressure is vented to atmosphere through DV and brake cylinder moves inwards. [pic] BRAKE CYLINDER Every coach fitted with air brake system, have two brake cylinders for actuating brake rigging for the application and release of brakes. During application of brakes the brake cylinder develops mechanical brake power by outward movements of its piston assembly, by receiving air pressure from auxiliary reservoir through the distributor valve.
This mechanical power is transmitted to the brake shoes through a combination of levers. During release action of brakes the compression spring provided in the brake cylinder brings back the rigging to its original position. The cylinder body is made out of sheet or cast iron and carries the mounting bracket, air inlet connection rib and flanges to the cylinder body a dome cover is fitted with the help of bolts and nuts. The dome cover enclosed the spring and passage for the piston trunk which is connected to the piston by screws.
The piston is cast iron having a groove in which piston packing is seated . piston packing is of oil and abrasion resistant rubber material and is snap fit to the piston head. The packing as self lubricating characteristic which ensure adequate lubrication over a long service period and extends seal life considerably. AUXILARY RESERVOIR The auxiliary reservoir is a cylindrical vessel made of sheet metal. On both the ends of the reservoir, flanges are provided for pipe connections. One end of the auxiliary reservoir is charged through the feed pipe to a pressure of 6 kg/cm2 .
At the bottom of the auxiliary reservoir, a drain cock is provided for draining out the condensate/moisture . The auxiliary reservoir should be overhauled in every POH. DISTRIBUTOR VALVE Distributor valve is the most important functional component of air brake system and is also referred as the heart of air brake system. The distributor valve sense drop and rise in brake pipe pressure for brake application and release capacity. It is connected to the brake pipe through branch pipe.
Various other components connected to the distributor valve are auxiliary reserve reservoir, brake cylinders and control reservoir. FUNCTION OF DISTRIBUTOR VALVE For application and release of brakes the brake pipe pressure has to be reduced and increased respectively with the help of driver’s brake vale. During these operations the distributor valve mainly performs the following function. i) Charges the brake system to regime pressure during normal running condition. ii) Help in graduated brake application, when pressure in brake pipe is reduced in steps. ii) Helps in graduated brake release, when pressure in brake pipe is increased in steps. iv) Quickly propagates reduction of pressure in brake pipe throughout the length of the train by arranging additional air pressure reduction locally inside the distributor valve. v) Limits maximum brake cylinder pressure for full service applicationemergency application. vi) Control the time for brake application and brake release depending on service conditions. vii) Facilitates complete discharge of air from the air brake system manually with the help of operating lever. iii) Protects overcharging of control reservoir when the brake pipe pressure is quickly increased for releasing the brakes. C3W DISTRIBUTOR VALVE The C3W distributor valve consists of: 1) Main body 2) Quick service valve 3) Main valve 4) Limiting device 5) Double release valve 6) Auxiliary reservoir check valve 7) Cut off valve 8) Application choke 9) Release choke OPERATION OF C3W DISTRIBUTOR VALVE For effective functioning of air brake system, the distributor valve has to operate effectively during 1) Charging stage 2) Application stage 3) Release stage 1) CHARGING STAGE
During charging stage the compressed air flows from the brake pipe and enters into the brake pipe chamber of main valve, cutoff valve and quick service valve. Due to this pressure the various valve get activated and perform as under MAIN VALVE Due to brake pipe pressure acting on top face of the large diaphragm, differential pressure acts on the main valve. As a result the hollow stem moves downward there by connecting brake cylinder to atmosphere. In addition these because of BP pressure at top of large diaphragm it press ring and trigger. This action unlocks the CR release valve by raising upward the locking rod.
CUT OFF VALVE As brake pipe pressure enters into the cut off valve it flows through the solex jet and valve, (which is held upon due to action of BP pressure on bottom side of the lower diaphragm) to the control reservoir, as the CR & BP pressure equalizes, diaphragm assembly comedown and valve reach to lap position. The control reservoir pressure now also reaches to the upper portion of top diaphragm of quick service valve and the bottom portion of large diaphragm of main valve simultaneously, the auxiliary reservoir is charged with BP pressure reaching from cut off valve chamber- via auxiliary reservoir check valve. ) APPLICATION STAGE EMERGENCY APPLICATION During emergency application the brake pipe pressure is reduced rapidly to 0 kg / cm2 by the driver’s brake valve. Because of this drop the position of the various valves will be as described below. MAIN VALVE: With drop in BP pressure to 0 kg / cm2 differential pressure acts across the large diaphragm. As a result the hollow stem is moved in upward direction and pushes the check valve there by opening the passage for entry of auxiliary reservoir pressure at top portion of main valve. This pressure then gets a way to break cylinder through limiting device.
The brake cylinder thus gets charged with the compressed air. This pressure is known as BC-pressure. LIMITING DEVICE The auxiliary reservoir pressure, which entered into the top position of main valve, now enters the limiting device through the valve, which is held open. From limiting device air pressure now enter the brake cylinder. When the BC pressure rises to 3. 8 kg / cm2 the upwards force on the diaphragm lifts the guide and the valve at the bottom of the limiting device gets closed. Thus further entry of air into the brake cylinder stops. When the brake cylinder pressure reaches 3. kg / cm2 this pressure i. e. BC pressure act on Top face of small diaphragm of main valve ? Bottom face of upper diaphragm of cut off valve ? Top (small chamber) of quick service valve Now because of this BC pressure acting at main valve small diaphragm, the hollow stem is pulled down. As a result the check valve at top comes down to close stage and assume lap position with the hollow stem closing further entry of AR pressure. CUT OFF VALVE: In cut off valve the bottom face of the upper diaphragm is subjected to BC pressure because of which guide is lifted.
Also the upper portion of lower diaphragm is subjected to CR pressure, which pushes the total assembly downwards. This action closes the valve off cut off valve, these by isolating it from control reservoir pressure. QUICK SERVICE VALVE In quick service valve BC pressure acts at the top of valve and control reservoir pressure act at top face of upper diaphragm, As a result the stem is pushed down BP pressure inside the DV is at “0” kg / cm2 the residue BP pressure from the bulb of quick service valve will flow back and vent to atmosphere with the BP line.
GRADUATED APPLICATION During graduated brake application the brake pipe pressure is draped in steps by driver is brake valve. The movement of various valve assemblies is almost in the some direction as during emergency application, but their movement is comparatively less. In the main valve however after each application the hollow stem assumes the lap position with the check valve. In addition to this during graduated application the bottom valve of limiting device is held open to allow compressed air to enter into brake cylinder. When BC pressure reaches 3. kg / cm2 the bottom valve in the limiting device gets closed, similarly at the time of full service application as the BC pressure reaches 3. 8 + 0. 1 kg / cm2 within specified time, the position of various valve assemblies will be the same as described above. 3) RELEASE STAGE When the brake pipe pressure is increased in steps for graduated release of breaks the position of different valve is as described below. MAIN VALVE At the top face of large diaphragm as the BP pressure increases, the hollow stem is moved down ward leaving its lap position with check valve.
The BC pressure thus finds a passage from top of hollow stem to exhaust to the atmosphere. This action reduces pressure on top of the upper diaphragm and the hollow stem engine lifts up to lap position. It closes the hollow stem top portion. The some cycle is repeated when BP is increased during next stage. In this way graduated release effect is obtained. CUT OFF VALVE; As the BP pressure increase the position of cut off valve remains similar as in graduated application i. e. the cut off valve will remain close isolating CR pressure from brake pipe pressure. QUICK SERVICE VALVE
When the BP pressure is increased then as explained above from the main valve the BC pressure gets exhausted to atmosphere. This action gradually reduces the BC pressure. When BC pressure reduces to 0. 8 kg / cm2 during brake release, the force at the top of the quick service valve, becomes comparatively less than BP pressure present in Quick service valve. As a result the valve at top gets lifted thereby giving passage to blocked BP pressure to atmosphere with the exhaust of BP pressure the quick services valve of the distributor valve again gets ready for next brake application. MANUAL RELEASE
Double release valve provides for accelerated manual brake release when is particularly useful during shunting operation. A short pull on the lever of double release valve is all that is needed. This action opens the control reservoir release chock valve, which is then held open by the locking rod, venting control reservoir through the open control reservoir release check valve brings the main valve to release position and exhaust the brake cylinder pressure through the hollow stem. PASSENGER EMERGENCY ALARM SYSTEM It consists of two components: 1. Passenger emergency alarm signal device (PEASD) 2. Passenger emergency alarm valve(PAEAV)
These two components in combination give an indication to the e driver that some passenger is in need to stop the train. The indication is transmitted from the coach when the passenger pulls the chain. Passenger Emergency Alarm Signal Device:- PEASD is a manually operated pilot vent valve. It is operated through mechanical force exerted by pulling the alarm chain provided inside the coaches for emergency use. Passenger Emergency Alarm Valve:- Passenger coaches are fitted with an alarm chain pull arrangement. Alarm chain is connected to the two PEASD which are situated at either side of one end wall of the coach.
PEASD’S are connected to the PEAV through a 10mm control pipe. BP pressure is fed to the PEAV through a 20mm branch pipe, in the event of alarm chain pull air is depleted form the control pipe connecting PEAV and PEASD causing BP pressure to exhaust through the 4 mm choke in the PEAV. This causes partial application of brakes. This drop in pressure in the brake pipe line is also observed in flow meter fitted in the locomotive for the driver to stop the train. LIFITING SHOP The main constructional and design feature of the ICF/RCF all-coil bogies, used on mainline BG coaches are briefly described as follows: |S. No. Description |Parameters | |1 |Maximum Axle load bearing |16,25t,13t | | |capacity | | |2 |Wheel base |2896 mm | |3 |Wheel Diameter |915 mm | |4 |Axle guidance |Telescopic axle guide with oil damping | |5 |Primary suspension |Coil spring | |6 |Secondary suspension |Coil spring | |7 |Shock absorbers |Vertical dashpot in primary suspension | | | |Hydraulic double acting vertical shock | | | |Absorber in secondary suspension. |8 |Transfer of coach body weight |Through bogie side bearer pitched | | | |at 1600mm | ALL-COIL ICF BOGIE The bogies being currently manufactured by ICF/RCF which have been accepted as standards of the Indian Railways and are of an all welded light weight construction. Axles are located on the bogie by telescopic dash pot and axle guide assemblies. Helical coil springs are used in both the primary and the secondary stages. The axle guide device provides viscous damping across primary springs while hydraulic dampers are provided across the secondary stage.
Dampers are protected against misalignment by resilient fittings. Isolation of vibration is effected by rubber pads in primary and secondary suspension. Deflection due to the tare weight is almost equally divided between axles and bolster springs. Weight of coach body is transferred to its bogie by side bearers consist of lubricated metal slides immersed in oil baths. No vertical weight transfer is affected through bogie pivot and the pivot acts merely as a centre of rotation and serves to transmit tractive / braking forces only. BOGIE ASSEMBLY The bogie frame and components are of all-welded light construction with a wheel base of 2. 896 metre.
The wheel sets are provided with self-aligning spherical roller bearings mounted in cast steel axle box housings. Helical coil springs are used in both primary and secondary suspension. The weight of the coach is transferred through side bearers on the bogie bolsters. The ends of the bogie bolsters rest on the bolster helical springs over the lower spring beam suspended from the bogie frame by the inclined swing links at an angle 70 . Hydraulic shock absorbers and dash pots are provided in the secondary and primary suspensions respectively to damp vertical oscillations. AXLE BOX GUIDE WITH DASH POT ARRANGEMENT Axle box guides are of cylindrical type welded to the bottom flanges of the bogie side frame with close dimensional accuracy.
These guides together with lower spring seats located over the axle box wings house the axle box springs and also serve as shock absorbers. These guides are fitted with guide caps having nine holes of diameter 5 mm equidistant through which oil in the lower spring seat passes under pressure during dynamic oscillation of coach and provide necessary damping to primary suspension to enhance better riding equality of coach. This type of rigid axle box guide arrangement eliminates any longitudinal or transverse relative movement between the axles and the bogie frame. The quantity of oil required to achieve 40 mm oil lever above the guide cap in modified arrangement is approximately 1. 6 liters and in unmodified arrangement is approximately 1. 4 litters. AIR VENT SCREWS
On the bogie side frames, directly above the dash-pots, tapped holes are provided for replenishing oil in the dash pots. Special screws with copper asbestos washers are screwed on the tapped hole to make it air light. BOGIE BOLSTER SUSPENSION The bolster rests on the bolster coil springs- two at each end, located on the lower spring beam which is suspended from the bogie side frame by means of bolster-spring-suspension (BSS) hangers on either side. The two anchor links diagonally positioned are provided with silent block bushes. The links prevent any relative movement between the bogie frame and coach body. SPRINGS In ICF bogie, helical springs are used in both primary and secondary suspension.
The springs are manufactured from peeled and centre less ground bar of chrome vanadium/chrome molybdenum steel conforming to STR No. WD-01-HLS-94(Rev. 1) CENTRE PIVOT ARRANGEMENT The centre pivot pin joins the body with the bogie and transmits the tractive and braking forces on the bogies. It does not transmit any vertical load. It is equipped with rubber silent block bushes which tend to centralize the bogies with respect to the body and, to some extent, control and damp the angular oscillations of the bogies SIDE BEARERS The side bearers are provided to support the weight of the coach. It consists of a machined steel wearing plate immersed in an oil bath and a floating bronze-wearing piece with a spherical top surface kept in it, on both sides of the bogie bolster.
The coach body rests on the top spherical surface of these bronze-wearing pieces through the corresponding attachment on the bottom of the body-bolster. The whole arrangement is provided with a cover to prevent entry of dust in the oil sump. ANCHOR LINKS The floating bogie bolster which supports the coach body is held in position longitudinally by the anchor links which are pinned to the bolster sides and the bogie Transoms. One anchor link is provided on each side of the bolster diagonally across. The links can swivel universally to permit the bolster to rise and fall and sway side wards. They are designed to take the tractive and braking forces. The anchor links are fitted with silent block bushes SILENT BLOCK
This is a synthetic rubber bush fitted in anchor link and center pivot of ICF bogies to transmit force without shock and reduce noise. EQUALISING STAYS This Device has been provided on bogies between the lower spring plank and the bolster to prevent lateral thrust on the bolster springs which have not been designed to take lateral force. These links have pin connection at both ends and therefore can swivel freely. BOLESTER SPRING SUSPENSION HANGERS (BSS HANGERS) In the secondary suspension the bolster is supported on helical coil springs which are placed on the lower spring plank is suspended from the bogie side frame through BSS hanger on hanger blocks. SHOCK ABSORBERS
Hydraulic shock absorber is also provided to work in parallel with the bolster springs to facilitate damping for vertical oscillations. WORKSHOP MAINTENANCE- BOGIE SHOP 1. Coach Lifting 2. Bogie cleaning 3. Bogie dismantling 4. Component cleaning 5. Attention to components 6. Repair of components 7. Bogie assembly 8. Load testing and adjustment 9. Lowering of coach 10. Final adjustment OBJECT:- To study inspection & testing procedure of helical spring of coaches also suggest methods of improvement to reduce rejection & prevention from corrosion. USE OF SPRINGS:- Springs are used in the suspension system of coaches to absorbs the jerks developed during running of coach and provide comfort to the passengers. INSPECTION OF SPRINGS:- Springs are inspected during every POH.
The inspection procedure is as follows: ? Springs which are lowered from the bogie are sent for the washing in spring section. Here the springs are dipped in the caustic soda tank for 12 to 16 hrs. so the oil, grease, scale etc are cleaned. ? Springs are then washed by the water jet. ? Visually inspect the springs for breakage, welding marks, cracks and corrosion pits. ? Shot peening for surface finish and fatigue relief of springs. ? Cracks are tested in magna flux machine. ? Coding of springs ? Anti corrosive coating of red oxide, and painted. ? Load test ? Grouping SHOT PEENING:- Shot peening is done for the surface finish and fatigue relief of springs.
In shot peening process small particles of chilled iron are blasted on the springs with high velocity, so these particles works as abrasive and take away a fine layer of metal with it. And the surface of springs looks clean. Rotary Table Type Shot Blasting machine is used for the shot peening process. This machine has two tables which alternately loaded by springs. The max. dia of job is 1800 mm and load carrying capacity is 2500kg.. At a time 25 axle box springs or 18 bolster springs can be shot peened by the machine. TESTING OF CRACKS:- It is nondestructive method of testing. Magna flux machine is used for detection of cracks in spring. The spring is first bathed by the solution of flouroscent, iron powder and kerosene.
Then the springs are magnetized by the machine with clamping in machine itself. When the springs are magnetized, the springs are lightened by the ultraviolet lamp. Since the process is done in the dark room, so if the springs have cracks then this flouroscent shines which penetrated in the springs due to crack ness and detection of cracks is done so the spring will rejected. LOAD TEST:- After coding and coating of paint the springs are sent to the load test. The springs are tested for the 2000ton load and this load is kept for 1 to 2 minutes. If the springs can sustain this load with limited deflection then springs are selected else rejected. METHODS OF IMPROVEMENT:- Use the springs made of standardized material as suggested by Railway’s Standard. ? The springs should be made of fine grained spring steel. ? Use the springs manufactured by the authentic company and also notice the manufacturing process of springs should be according to the standardized method. ? 100% of springs should be checked for all the test procedure. PREVENTION FROM CORROSION:- Springs should be coated with the anticorrosive paint and black bituminous paint. ———————– Technician 2 Technician 1 Senior technician Supervisor Supervisor Junior Engineer 2 Junior Engineer 2 Junior Engineer 1 Junior Engineer 1 Section Engineer Senior Section Engineer (SSE) Helper