what does the MU cables do ?
A modern MU system consists of cables and hoses.
The MU cable (one, usually at or near sill level) connects the locomotive controls (throttle, dynamic brake, alarms etc.) between engines so that the whole consist may be operated from the head end. On modern engines this includes control of sanders.
The MU hoses (3 or 4 on each side of the couplers) interconnect the pneumatic systems of the locomotives to control brakes. On older engines with pneumatically-controlled sanders there were 4 MU hoses; modern engines have electric sander control and only have 3 hoses. The hoses are duplicated on each side of the coupler for redundancy - all hoses must be connected between engines in a consist.
Most MU systems have been compatible from very early on. A noteworthy exception was Baldwin, which used an all-pneumatic MU system and were incompatible with Alco/MLW, EMD and GE locomotives.
There is one more hose - the train line or “hosebag” located to the right of the coupler when facing the pilot. It connects the brake pipes on all the cars and locomotives in the train. Every locomotive or car with air brakes has one of those.
Last but not least, engines used with passenger cars set up for head-end electrical power (HEP) will have HEP cable connections, regardless of whether that particular engine generates power for the cars.
Links the Leader to the trailing units to control them as well…also there are fuel transfer hoses as well to other units
Uh, no, there aren’t…except in a few very special cases where there was also a fuel tender involved, such as was experimented with on Burlington Northern.
In the case of slug mothers, there will also be additional heavy cables to carry current from the main generator of the mother to the traction motors of the slug. Some slugs carried auxiliary fuel tanks so there would also be a fuel line.
uhh yeah thats what im talking about expecially on the old bn green weenies