The standard coach which was developed after first World War was a wooden coach on steel underframe (4-wheeled). Later bogie coaches with the wooden body and steel underframe were developed (IRS coach). Further developments have since taken place to provide more built-in strength and to make the coach lighter.
Now ICF anti-telescopic integral coach with all coil spring bogies have been made a standard design for Indian Railways which has a better riding quality compared to IRS design coach.
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
LHB Coaches And FIAT BOGIE:
The coaches are approximately 2.2m longer than the standard ICF-built integral coaches (two additional rows of the chair cars, one additional sleeping bay for the sleeper coaches). The AC coaches are expected to carry 78 passengers. The body is by Alsthom LHB, with a stainless steel construction, mounted on Fiat bogies with disc brakes.