On the cover of the 2005 BNSF annual report there is a photo of the front of a brand new loco coming off the assembly line at Erie, PA. On either side of the coupler are three hoses labeled A&R, ACT and MR. What do those letters stand for? Also, there is a orange colored hose above the coupler with both ends plugged into a receptacle and supported in the middle with a bracket and short chain. What is that hose for?
Apply and Release
Actuating
Main Reservoir.
That’s the MU cable (Multiple Unit), which permits the trailing locomotives to be controlled from the control stand on the controlling unit.
Both ends are plugged in to protect the end of the cable. One end is in a dummy receptacle–that end would be pulled out and inserted into the live receptacle of an adjoining unit if they were being lashed together.
Thank you very much for the informative replies.