Testing and Validation of Long Trains Under High Flow and Gradient Conditions

The need to extend train lengths has been a primary business target of the railway industry, due to its obvious benefits. However, winter train operating conditions, excessive in-train slack action, deterioration of air brake signal propagation and the added stress on infrastructure and equipment has naturally kept the average train lengths at bay. The introduction of advanced equipment, new concepts and strategies have now enabled Canadian Pacific to change this mindset. Long Train make up is now very possible, taking into account the Distributed Power configuration. Making a very long train resemble a series of short trains coupled together, each with its own locomotives, synchronously connected to the Lead unit’s commands, makes such trains very safe and efficient. Extensive Field Testing and Train Simulation work done over the last two years at CP has shown that with the use of Multiple Remote Locomotive set-up, it is in fact very possible to safely contemplate extending the limits of today’s maximum allowed 60 CFM of total train air flow, into uncharted territory, possibly approaching a total of 90 CFM. CP has pursued to implement on a permanent basis, operating instructions that would permit Multiple Distributed Power trains to depart from a train brake test location with combined air flow of up to 90 CFM, provided the flow at each DP locomotive consist is not greater than 60 CFM and train length sections between locomotives are not exceeded. This paper investigates the operation of Distributed Power trains at higher levels of air flow and, through detail field testing and evaluation techniques, substantiates the validity of extending the safety limits of train leakage and gradient for such trains.