| Résumé | With funding from Transport Canada (TC), the National Research Council of Canada (NRC) previously performed cold-weather air brake research which included multiple separate testing programs. This technical brief presents the results from controlled testing of two pre-production freight railway air brake cylinders with built-in automatic parking brake (APB) capability. The APB function is seen by the railway industry as providing an additional means of securement beyond that provided by the handbrakes, as APBs offer the ability to mechanically lock the brake piston in an extended position without manual intervention following a pneumatic brake application. The APB systems were installed on a freight railcar in direct replacement of the standard brake cylinder and subjected to both service and emergency brake applications at nominal brake pipe pressures of 90 psi. Additionally, the same APB-equipped cylinders were tested in an individual railcar air brake test rig. Findings show that the APB-equipped cylinders are effective at maintaining brake force following emergency brake applications, even after all air was evacuated from the brake cylinders, with minimal performance degradation in routine brake functions and no significant impact on handbrake operation.
Results demonstrate that implementation of the APB equipment into interchange operations has the potential to improve railway safety. However, the practical implementation may present integration challenges with railway operations that should be addressed prior to deployment into service by the railway industry. Additional field trials in a railway interchange operation would provide data to better understand how likely the APB-equipped cylinder is to retain braking force, and what benefits this provides during routine and emergency air brake applications. |
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