Abstract: In a track maintenance vehicle, a cross tie exchanging mechanism is mounted on the vehicle comprising jaws which grip the end of the cross tie to be removed and operate to pull the cross tie from the road bed laterally from beneath the track rail and also operate to push a new cross tie laterally beneath the rails into the road bed. Rail clamps are provided to grip each rail at two spaced positions along each track rail to prevent the track rail from flexing when the track rail is unfastened from the cross tie to be removed. The rail clamps are also used to lift the track rails clear of the cross ties prior to operation of the tie exchanging mechanism to remove and replace a cross tie. A beam member supports the rail clamp so that the rails are laterally stabilized when lifted. The beam member is continuously laterally positioned independent of the lateral moveent of the vehicle by a guide member relative to the rails when the rail clamp is not engaged with the rails.

Abstract: A compact bidirectionally operative tie exchanging apparatus includes an extensible telescoping beam assembly carried in a support cradle mounted on the underside of a railway maintenance car. The beam assembly includes an inner and an outer beam telescopically received within one another with hydraulically actuated tie clamping arms mounted on the opposite, remote ends of the beam assembly. A push/pull hydraulic cylinder has its ram and its cylinder connected, respectively, to the inner and outer beams. Hydraulically actuated locking pins mounted on the support cradle are selectively actuatable to lock either the inner beam or the outer beam to its respective support cradle.

Abstract: A compact bidirectionally operative tie exchanging apparatus includes an extensible telescoping beam assembly carried in a support cradle mounted on the underside of a railway maintenance car. In a first embodiment, the beam assembly includes an inner and an outer beam telescopically received within one another with hydraulically actuated tie clamping arms mounted on the opposite, remote ends of the beams assembly. A push/pull hydraulic cylinder has its ram and its cylinder connected, respectively, to the inner and outer beams. Hydraulically actuated locking pins mounted on the support cradle are selectively actuatable to lock either the inner beam or the outer beam to its respective support cradle.

Abstract: In a track tamping machine, opposed pivotally mounted tamping arms are oscillated by respective single acting hydraulic cylinders controlled by one or more hydraulic duplex rotary distributing valves. Fluid supply and return lines for each piston assembly are connected to a source of pressurized hydraulic fluid by way of a respective rotary valve. Each valve has a stationary ported shell which receives a rotary cylindrical spool having a pair of axially displaced supply and return throughports which alternately register with supply and return line ports in the shell to open and close the connections between the oscillating cylinder and the supply and return lines. Such oscillating cylinders are useful in controlling the vibration of the tamper arms in a track tamper unit.

Abstract: Opposed pivotally mounted tamper arms are oscillated by respective single-acting hyraulic piston assemblies controlled by separate hydraulic duplex rotary distributing valves. Fluid supply and return lines for each piston assembly are connected to a source of pressurized hydraulic fluid via the respective rotary valve. Each valve has a stationary ported shell which receives a rotary cylindrical spool having a pair of axially displaced supply and return throughports which alternately register with supply and return line ports in the shell to open and close the connections between the respective piston assembly and the supply and return lines. While the rotary valves are preferably driven by a common drive unit, the relative phase of the oscillations of the arms can be determined by rotationally offsetting one of the spools with respect to the other by the desired phase angle.

Abstract: Opposed pivotally mounted tamper arms are oscillated by respective single-acting hydraulic piston assemblies controlled by separate hydraulic duplex rotary distributing valves. Fluid supply and return lines for each piston assembly are connected to a source of pressurized hydraulic fluid via the respective rotary valve. Each valve has a stationary ported shell which receives a rotary cylindrical spool having a pair of axially displaced supply and return throughports which alternately register with supply and return line ports in the shell to open and close the connections between the respective piston assembly and the supply and return lines. While the rotary valves are preferably driven by a common drive unit, the relative phase of the oscillations of the arms can be determined by rotationally offsetting one of the spools with respect to the other by the desired phase angle.