In case anyone looking at the photo of SIRT 18 was wondering about those lines running to the forward and rear headlamps, they are NOT electric wires! Those 1892 headlamps were lit with coal oil.|
The lines are emergency cord connections, The emergency cord runs through each car in the train.
With the Eames vacuum brake, the emergency cord on each car is connected to that of the next car and locomotive when coupling. Pulling on an emergency cord is very serious business!
When that emergency cord is pulled, it releases vacuum in the brake system at the locomotive's control valve. There are no control valves or reservoirs on cars with vacuum brakes, only the piping and truck mounted brake cylinders. The engineer (with the conductor's consent), resets the brake and recovers vacuum to let the brakes off if all is OK to continue.
With Westinghouse air brakes, the emergency cord in each car is independent and not connected through to the locomotive. When pulled, it opens a valve on that car, which in turn puts the brakes into emergency mode for the whole train. That valve must be manually reset before the air brake system can be pumped up for the train to roll again.
In both cases, vacuum or air brake, it requires the conductor (if he did not pull the cord), to find out why the train was stopped. All couplings and hose connections must be examined, as well as the emergency cord in each car to see if any had been pulled. The end of an emergency cord had a knob or handle which if pulled would leave hanging it lower than its set mark on the wall. The conductor also needs to find out (if possible) who pulled it and why.
Recovery from an emergency stop takes time and must be reported to the dispatcher as well because the train will be running late, if found safe to continue on.