The practice of placing loaded stock cars at the front of a train, behind the motive power, was to minimize the possibility of animal injuries or death, due to rough car action as slack ran in and out while running. It's also the cause load shifting and damaged freight in the cars.
The farther back a car was in a train, the more severe that action could be. Cabooses riding at the rear of a train had long handrails attached to the ceiling, end to end. The crew members riding there were ever mind full about slack action. Even then, some were seriously injured at times.
S. Islander
