IRS coaches were heavy and used to suffer extensive damage in collision/accident resulting in heavy passenger casualties. The integral design was developed in the late 30s in Switzerland by M/s Swiss Car and Elevator Mfg. Ltd. Schlieren This could be visualized as a large hollow tube placed on wheels. Extensive use of advanced welding technology for sheet welding was made use.
Indian Railway obtained collaboration with this firm and set up the coach factory at Perambur, Madras in the 1950s. The concept of separate coach body and underframe gave way to one piece single shell construction.
The shell consists of pressed steel section welded together with sheet covering. The skeleton of the shell consists of a series of hoops each consisting of floor cross beam, body side pillars, and roof carlines. The sole bar, waist rail, light rail, cant rail and roof purlines hold these hoops together. This is covered by roof sheet on top, side panels on sides and corrugated trough floor.
The trough floor offers considerable resistance to longitudinal crushing loads but cannot take the high vertical load. On each end, specially designed headstock with compression/destruction tubes are welded. These tubes when subjected to collision shock, get deformed absorbing most of the energy hence reducing the adverse effect of impact. Body bolsters are welded on the bottom side of trough floor.
The coach ends consist of 4 vertical stanchions box section, transversely connected by Z sections and are welded to the headstock. Collision impact is first received by end stanchions which absorb a large part of it. The residual shock is absorbed by deformation of compression/destruction tubes. These features make ICF coaches anti-telescopic. The windows are made separately and screwed on to the double chamber. The coaches can be provided with vestibules for passage from one coach to another in a running train.
The bogie frame is made from sections welded together. The axles are located on bogie by telescopic dash pots and axle guide assemblies. Helical
springs are used in both primary and secondary suspensions. The axle guide provides damping across primary suspension and vertical shock absorber across secondary suspension. Rubber pad vibration isolation is also provided in the primary suspension. Weight is transferred through side bearers. Coach/
Bogie pivot only acts as centering device and transmits tractive/braking forces. Lateral shock absorbers are provided to dampen lateral vibrations.
Following are important features of furnishing :
- Length of the seat should not be less than 6’- 6″.
- The width of the seat should not be less than 21″ for second class and 26″ for first class.
- Hip width per passenger should not be less than 21″.
- The height of seat should be 16″ from the floor.
- Knee space between opposite seats should not be less than 21″.
Coding of coaching Stock:
Coaches are coded as per end user and are same for all gauges. There are a large number of codes the important codes are :
Coaching Stock Maintenance:
Coaches are based at a primary maintenance depot which is responsible for maintenance of those coaches. A set of coaches which are combined to form a train is called a rake.Rakes are given Primary maintenance by the owning railway / base depot and Secondary maintenance at the other terminus. No secondary maintenance is required if the round trip of the train is less than 3500 kms.
Other depots en-route undertake safe-to-run examination of the train. While primary maintenance involves complete inspection and attention to the rake, secondary maintenance involves cleaning, washing and inspection of safety fittings.
The target availability for non-AC coaches is 90%, i.e. 10% ineffective is permitted- 6.5% on workshop account for POH and repairs, 1% for waiting in yards and 2.5% on open line repair account. For AC coaches 12% ineffective is permitted- 9% on workshop account and 3% on open line repair.