In still rarer cases both a leading and a trailing bogie have been fitted.
Miller, delivered to the South Carolina railroad in 1834, presented a feature which has remained characteristic of American locomotives - the front part was supported on a four-wheeled swivelling bogie-truck, a device, however, which had been applied to Puffing Billy in England when it was rebuilt in 1815.
In any case the details depend upon whether the vehicle concerned is an engine, a wagon or a passenger coach, and upon whether it runs on bogie-trucks or not.
Aspinall on the Lancashire & Yorkshire railway to ascertain the resistance of trains of bogie passenger carriages of different lengths at varying speeds, and the results are recorded in a paper, " Train Resistance," Proc. Inst.
17, four values of L being taken for formula (12) corresponding to trains of 5, 10, 15 and 20 bogie carriages.