Selectable grade and uniform net shoe force braking for railway freight vehicle

Railway freight brake apparatus for on-board operation of rail vehicles in a train, such vehicles having a mechanical brake with friction brake shoes actuated by a pneumatic brake cylinder, and having a reservoir as a source of pressurized fluid, such apparatus comprising:

• (a) brake signal receiver on-board such vehicle to receive a brake signal indicative of a desired braking level of such vehicle;
• (b) at least one valve to control the pressurization of such brake cylinder from such reservoir and the depressurization of such brake cylinder;
• (c) processor to control said valve to supply such brake cylinder with pneumatic fluid from such reservoir to apply and release such mechanical brake in response to said brake signal;
• and
• (d) said processor controlling said valve to supply said brake cylinder with fluid pressure from such reservoir and to exhaust such fluid so as to produce generally equal net shoe forces on such brake shoes among such vehicles.

A method of controlling the braking of vehicles in a train having at least one locomotive and a plurality of freight vehicles, such method comprising:

• (a) transmitting from such locomotive a brake signal indicative of a desired braking level of such train;
• (b) selectively transmitting a grade signal from said locomotive when said locomotive is descending a grade;
• (c) receiving said brake signal and said grade signal on-board freight vehicles in said train;
• (d) processing said signals on-board such freight vehicles to control pressurization and depressurization of brake cylinders to apply and release friction brake shoes on such vehicles;
• and
• (e) controlling the brake cylinder pressure on such freight vehicle in response to receipt of a grade signal so as to provide generally equal forces on respective brake shoes among such freight vehicles.