Abstract: An applicator adapted to apply chemically-impregnated pads (53) to freshly-milled surfaces (24) on railroad ties (22), includes a vehicle (21) adapted to be moved along the ties; a carriage (29) mounted for horizontal movement with the vehicle along the ties, and mounted for floating vertical movement relative to the vehicle during use; sensors (51,52) for determining the position of a tie beneath the carriage; a pad storage magazine (33) mounted on said carriage; suction cups (38) and an actuator (47) for withdrawing an end pad from the magazine; a rotary motor and a lifting actuator (36) for moving a withdrawn pad from the magazine to a freshly-milled surface on a tie; and a nailer (39) for attaching the pad to the tie.

Abstract: An "active" suspension system provides two parallel force-transmitting paths between the body and wheel of a vehicle. The first path has a main spring (41), and the second path includes an actuator (42) and a spring (43). LVDT's (53,55) are arranged to monitor the displacements of the actuator (42) and the spring (43). The actuator is arranged in a high-gain closed position or velocity servoloop. The actual force (F.sub.w) exerted by the suspension system on the body is determined and compared with a desired force (F.sub.c) to produce a force error signal (F.sub.e). The force error signal (F.sub.e) is converted to a command signal supplied to the servoloop. The servoloop operates the actuator (42) so as to continuously drive the force error signal (F.sub.e) toward zero.