In the Locotrol system, I'm guessing that a radio signal from lead locomotive goes through a decoder and becomes an electrical signal to control the governors solenoids and dynamic braking system. But what about the air brakes? Does it use servos to actuate the valves, or perhaps another solenoid operated dump valve in the train line?
TRAINS does a good job of describing what goes on in a system but seldom explains how. BTW, are Woodward PG governors still used in locomotives?
The 'remote' receiver/decoder sends the signal to the MU/Air Brake/DB using electronic and electro pneumatic controls in the engine(depending on the model). If there are additional engines MU'ed to that engine, they are translated via the normal 'wired' MU connections. Don't try to read to far into this stuff. This is just a 'wireless' connection. The only difference is that the train line air brake function can be split to provide another set of air compressors deep in the train(better braking performance).
The 'dump valve' is in the FRED, and is controlled via the lead locomotive(via radio signal). With Locotrol back in the 70's, just about everything was controlled by some kind of electro pneumatic control like you described. Current 'high tech' engines are designed with computer controlled engine functions and lend themselves to DPU integration.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
jrbernier The 'remote' receiver/decoder sends the signal to the MU/Air Brake/DB using electronic and electro pneumatic controls in the engine(depending on the model). If there are additional engines MU'ed to that engine, they are translated via the normal 'wired' MU connections. Don't try to read to far into this stuff. This is just a 'wireless' connection. The only difference is that the train line air brake function can be split to provide another set of air compressors deep in the train(better braking performance). The 'dump valve' is in the FRED, and is controlled via the lead locomotive(via radio signal). With Locotrol back in the 70's, just about everything was controlled by some kind of electro pneumatic control like you described. Current 'high tech' engines are designed with computer controlled engine functions and lend themselves to DPU integration. Jim
So modern locomotives are essentially "Drive-by-wire?
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
Thanks for the info guys. My analysis wasn't too far off.
carnej1 So modern locomotives are essentially "Drive-by-wire?
Most modern EMD & GE locomotives has electronically controlled braking, and throttle response. The 'computer' controls all of this. EPA exhaust regulations make critical control of the diesel fuel burn so that the locomotive meets the current emissions standards. The GE C40-8 was one of the first locomotives to successfully integrate these controls. Without these micro processor controls, emissions and high levels of traction control would still be a dream.
Throttle control has been electrically controlled for many years, the traction control was next, and the air brake controls have followed..
conlejw TRAINS does a good job of describing what goes on in a system but seldom explains how. BTW, are Woodward PG governors still used in locomotives?
The last locomotives with a woodward governors were the early SD70's and early C44-9w's. About the only thing I miss on them was you could always get one of the old birds to start if you had control of the layshaft and enough batts/ jumpers/welders to get it to crank over. With the new ECU's if the computer doesn't see the correct voltage it will never fire. Makes for a lot of cursing when someone shuts a unit down in Texas then sends it back north to try and start it in the winter.
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