bolster wagon

bolster wagon (plural bolster wagons)

1. (rail transport) A flat or low-sided wagon, typically four-wheeled in contrast to a bogie bolster wagon with eight wheels, fitted with one or more heavy wooden baulks (bolsters), usually mounted transversely on its deck to support the load it carries. Two or more wagons can be coupled to carry a long load.
   • 1944 September and October, T. F. Cameron, “The Distribution of Rolling Stock”, in Railway Magazine, page 269:

     Bolster wagons are wagons fitted with heavy timber baulks which enable steel rails, long timber or similar traffic to be carried above the very low wagon sides. Single bolsters are used in groups of up to five. When five single bolsters are used in a set the load is secured to the second and fourth bolsters, but it must rest on all five wagons. In such a case the total weight of the load must not exceed two-thirds of the total carrying capacity of the five wagons. Twin bolsters are single bolsters permanently coupled, and double bolster wagons carry two bolsters apiece.

• bogie bolster wagon