The preparations extended into many forms of railway activity. It was naturally expected that casualties would be very heavy, and extensive arrangements were made for the running of ambulance trains. The working prepared for those allocated to the American Army was interesting. These trains, equipped for working on the Continent or at home, were fitted with the Westinghouse brake. For service within Great Britain LNER locomotives of the former Great Eastern 4-6-0 class B12 were used. These had the Westinghouse brake, and were generally acceptable because their low-axle loading
gave them a very high route-availability. Their crews, drivers, firemen, guards lived with the trains and worked rotationally on the caboose system. Although they had certain bases of operation they were so organised that the trains could be ordered anywhere, at any time of the day or night. The needs of the service frequently took drivers over unfamiliar routes, and then of course they had to be accompanied by local pilotmen. Furthermore, while the rebuilt variety of the B12 was an excellent engine and rendered invaluable and trouble-free service, some routes over which these heavy ambulance trains were ordered included severe gradients, where double-heading was necessary. On such occasions control of the train, and with it the brakes, was vested in the assistant engine, which in almost every instance would be vacuum-braked. The ex-Great Eastern 4-6-0s were fitted with vacuum-air proportional valves, so that the leading driver could work in his normal manner and apply the air brakes on the train engine and the coaches to an appropriate degree.
