Trains brakes are pneumatically actuated and use the same pneumatic line for power and signal transmission. This simple architecture presents limits for long trains since the last vehicles brakes receive a very delayed command and the train speed must be limited. Solutions were proposed using a signal transmission line parallel to the pneumatic line. These systems, though effective, present drawbacks and are of difficult implementation as retrofits. A solution is described, which leaves the braking system unchanged, but reduces the time delay in the signal transmission by adding a pneumotronic unit at the pneumatic line end. This unit analyzes the pressure time history, recognizes the precursors of new braking commands and issues inputs to a valve at the pneumatic line end mirroring the commands to the master valve. The rapidity of the braking action is enhanced, thereby allowing a more uniform braking and a speed increase of long freight trains.

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