Leakage Test On Distributed Power Trains


Did you know that when a leakage test is required on a distributed power train, the automated leakage test function is still required.


Prior to the new System Special Instructions being issued, a general order was issued removing the leakage test from Rule 33.7.3. With the new SSI, it is still gone from this rule. The leakage test was only removed from the set up process when linking up. 33.7.8 is the process for setting up the lead unit on DP train. Step 17 used to be the leakage test and was removed. Therefore the leakage test is no longer required during the linking process.


The chart in Rule 30.10.1 shows when a leakage test is required.


Remember, a leakage test is not required when performing a transfer train air brake test.


The obvious time a leakage test is required is when a Class 1 or Class 1A is required on your train or when a Class 1 is required on cars being added to your train. A leakage test is also required is when your cars have been given a Class 1 using a yard air test plant. One place this is done is at the Alton and Southern. While the cars connected to yard air, the carman has a valve that can be used to apply and release the brakes without the use of a locomotive. When you put your engine on, all you then have to do is an application and release and one of the required leakage test from 30.11.2.


Rule 30.11.2 list the three different types of required leakage test.


Part A is the Air Flow Method, which is preferred. This is if you have the proper gauge.


Part B is the old style 3 minute process when you lack an air flow meter or do not have the proper type.


Part C is the part I wanted to draw your attention to. It states that the DP system’s automated brake pipe leakage function must be performed on DP trains.


In summary, the automated brake pipe leakage function was removed from the set up process when linking up the DPU.  It is still required to be used when a leakage test is required when you have a DP train.