Air Brakes and Train Handling Rules - Alaska Railroad

63 Train Equipment and Operation63.13 Using Retaining ValvesThe normal position for retaining valves is in the EX (Direct Exhaust)position. Retaining valves are not necessary if locomotive dynamicbrakes and train brakes are functioning properly.Use retaining valves only when the train crew decides that the traincannot be handled safely in the normal manner.Follow these requirements when retainers are necessary:1. Notify the train dispatcher immediately.2. Apply the minimum number of retainers in the following positions:• Loaded cars—HP (high pressure) position• Empty cars—LP (low pressure) or SD (slow direct exhaust)position3. Begin at the head end of the train in blocks of at least 10 cars.NOTE: Also refer to Figure 67-F, Three-Position RetainingValve, in Chapter 67.63-16 ARRC Air Brakes and Train Handling Manual June 1, 1996