trailing truck

noun1

1. •
   On a steam locomotive, a railroad truck to which wheel axles (and, hence, wheels) for one or more coupled pairs of unpowered wheels are attached through bearings, located behind the driving wheels.

   • After trying but not mass-producing a heavy Pacific and tabulating indifferent tests of a three-cylinder 4-8-2, Central was in a mood to explore the possibilities of four-wheel trailing trucks. — 1959