Telescoping (rail cars)

In a railway accident, telescoping occurs when the underframe of one vehicle overrides that of another, and smashes through the second vehicle's body.

The term is derived from the resulting appearance of the two vehicle bodies: the body of one vehicle may appear to be slid inside the other like the tubes of a collapsible telescope – the body sides, roof and underframe of the latter vehicle being forced apart from each other.

The chances of telescoping can be reduced by use of anticlimbers and other structural systems which direct crash energy and debris away from the passenger and crew areas.

[2] One such energy absorbing system is the Green Buffer, winners of the 2023 Swedish Steel Prize,[3] where a collapsing steel structure in the buffers dissipate energy similarly to the crumple zones used in the automotive industry.

Accidents where telescoping occurred are numerous and include: To reduce the chance of telescoping, rail and tramway vehicles are often provided with an anticlimber: a horizontally ridged plate at the end of the chassis, which in a collision will engage with the anticlimber on the next car.

Cars of the Washington Metro were telescoped in this November 3, 2004 accident at Woodley Park station.
Interior of Washington Metro car 1077 following telescoping in a head-on collision . This car sustained a loss of 34 linear feet of passenger compartment space (nearly half the car) due to telescoping.