Look at pictures of Bristol Barrow Road overlooking the yard off a bridge front and rear of depot , giving a good idea of what happens including ash disposal . In the inefficient old railway everything came and went by rail to depots , spares in vans , brake blocks / wheel sets in open wagons , lubricating oil in drums , larger diesel depots in tankers , even the paperwork . In the efficient modern railway nothing goes by rail just creates more traffic on the roads .