Side dumping railroad car

A side dumping railway car comprising in combination:

• a plurality of wheeled trucks;
• a main car frame carried on said trucks;
• transverse support bolsters on said main car frame having pivot cradle means thereon;
• a hopper resting in said pivot cradle means;
• hydraulic cylinder means comprising a single hydraulic cylinder at each end of the car connected to a pivot point on said main car frame at one end of the cylinder and to a pivot point on the hopper at the other end of the cylinder, said pivot points positioned generally on the centerline of the car to permit generally vertical lifting of the hopper relative to the main car frame;
• hopper retaining means on each side of the car adapted to hold down one side of the hopper when said hopper is raised by said hydraulic cylinder means so as to raise the hopper on the side opposite said one side, said hopper retaining means comprising a hydraulically moved engagement lug on said main car frame adapted to slide into position to hold down a reaction pin, said reaction pin connected to one side of said hopper;
• an air to oil pressure intensifier on said car adapted to pump oil from a reservoir to an oil accumulator, the pressurized oil from said accumulator connected through tilt control valves to operate the hydraulic cylinders;
• and
• an interlock valve means between said tilt control valves and a latch valve means to prevent the passage of pressurized oil to the hydraulically moved engagement lug when the hopper is raised from the main car frame, said latch valve means operated by the movement of said engagement lug into position against said reaction pin and adapted to pass pressurized oil to the lifting hydraulic cylinder means only after said engagement lug has slid into position to hold down said reaction pin.