ANALYSIS AND SIMULATION OF THE PNEUMATIC BRAKING SYSTEM OF FREIGHT TRAINS
In North America, and in many other parts of the world, freight trains still employ pneumatic equipment for braking. The 26C locomotive valve and control valves of the cars are connected by a brake pipe which serves the dual purpose of conducting pneumatic power and transmitting the control signal (brake signal) from the locomotive to each car of the train. The development of the air brake system has been largely empirical and experimental, which may take years to develop a new design. In this thesis, a new brake pipe mathematical model is developed, including the interaction of the branch pipe. Two different numerical methods (finite difference and finite element techniques) are developed to provide transient and steady state solutions for the new brake pipe model with leakage. Two mathematical models are developed to describe and study the dynamic behaviour of the 26C locomotive valve parts, namely the complete and modified models. The combination of the implicit finite difference solution technique and the modified model of the 26C valve are found to be better than any other of the present developed combinations for providing an accurate and fast simulation. Mathematical models for the ABD/ABDW subvalves are developed and incorporated with the air brake system model. The new mathematical models for the ABD/ABDW are capable of describing the dynamic behaviour of these valves for any of the several application modes (service, emergency, recharge, dry charge and recharge after emergency). These models and numerical techniques were used to develop a simulation program for the air brake system. This Fortran program is a very good tool to analyze and simulate the transient and steady state behaviour of the air brake system.
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