When double-heading, how did the two crews communicate?
Tony CVummins
By whistle signals. Lead loco controled the brakes. Both engineers would have been familiar with the route and usual actions at usual locations.
Mac
The trailing loco controled the operation with whistle signals.The trailing loco was used because the whistle of the lead loco could not be heard by the crew in the trailing loco.
The UK’s Great Western Railway adopted pretty strict Regulations in such circustances following an accident in my neck of the woods back in October 1904, when an assisting 0-6-0 Saddle Tank engine was coupled ahead of the 4-4-0 Tendr Engine for the climb up the 1 in 50 from Gowerton to Cockett Station in the Swansea suburbs.
The much smaller assisting engine derailed at speed, and the accident resulted in the deafh of passengers and crew members. That experience led the Company to lay down strict conditions of where the assisting engine should be coupled in relation to the train engine, with specified exceptions for various classes…
I also understand that where an assisting engine was coupled ahead of the train engine, its driver would control braking to respond to signals, speed restrictions, but the driver of the train engine was to control braking for service stops at stations.
P.S. The Great Western was unique in the UK in having a second whistle, the Brake Whistle, whose pitch was quite different to the main whistle, and which was to be used to warn every other engine in the immediate area to bring their trains, shunts. etc. to a halt without delay.
I am just curious about how the lead loco could hear the whistle of loco 2, but the second one couldnt hear loco number 1? Dont make sense as the lead locomotives whistle would be carrying backwards faster than forwards doppler wise. SP on Tehachapi had speakers so the swing and pusher could hear the whistle signals of the road unit and vice versa when they stopped for water.
Depending on the railroad either the lead was the helper or the road unit.
Fired and cut coal on a number of Southern Ry. doubleheaded excursions in the 1970s and neither engine crew had any trouble hearing the whistle of the other engine. Of course, we were generally traveling at subsonic speeds . . . 8^)
Old Timer
errr, not quite, the Doppler efect alters the apparant pitch of the sound, not the speed of it, and only applies when there is relative movement between the source and listener.
Depending on the size of the whistle’s horn opening (if there is a horn, not essential with many whistles), whistle placement and pitch, their can be some directional characteristics to the sound which in such cases are usually arranged to favor projection in front of the train to assist in alerting people ahead of the train.
Whistle signals were used to communicate with mid-train and pusher helpers, IIRC. Shouldn’t have been any problem in most cases communicating with the other locomotive(s) at the head end.