(potential) dumb question - what are "m.u. hoses"?

Model Railroader General Discussion (Model Railroader)
1

I’ve seen this term used a lot, but have never seen what “m.u.” stands for. I know they’re the hoses that look like compressed air lines sticking out of locos near the coupler, but I’m not sure exactly what they are and what their purpose is. Can somebody please shed some light on this mystery for me? Thanks in advance.

Cheers,

2

MU stands for Multiple Unit. They connect the locomotives couple together so that the engineer can control all units.

3

There are four types of connectors in this photo:

  1. The coupler (obvious)
  2. The brake line (the thick one at thebottom)
  3. The MU Electrical connections (they go between the walkways)
  4. The MU hoses (all the little ones at coupler height).

As to what all the MU hoses do… sorry, I can’t answer that one.

4

The “M.U.” hoses connect the multiple units together to act as a single engine. A tractor-trailer driver can control the brakes of his trailer separately from the tractor. A locomotive engineer has no independent control of the trailing units. If the engineer sets his control at run 8, the trailing units will also operate at run 8. Otherwise, each unit would have have its’ own engineer operating that locomotive. This was one of the reasons diesel enginers supplanted steam enginees so readily. One engineer and brakeman could operate any number of diesel engines lashed together. The steam engines, if double or triple-headed, had to have an engineer and fireman in each locomotive. The controlling engine used whistle signals to tell the other crews whether to pour-it-on or hold back.

5

Thanks, everybody, for the information. That really clears things up.

6

Just remeber the dumbest question is the one not asked. A year ago I didn’t know the answer to the same question and I had to ask another modeller (Wow my spelling is horrible). The nice thing about our hobby is that most are very willing to pass along what they know.

Jesse