Diesel MU hoses

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New Member
I'm modeling some Milwaukee Road SD40-2's in HO scale.

Many of their SD40-2's were missing some or all of the MU hoses. I know railroads use either 3 or 4, their uses well documented elsewhere on the internet, but no mention of the use of less.

The units I am modeling are the radio control masters, and were therefor used primarily on the lead. Would the lead-only status result in no need for possibly damage-prone hoses? Or is there some applications where a road would use less than 3 or 4?

The unit in particular is #21. Most photos of it in the late 1970's show it missing most of it's MU air hoses. Looks like when it only has one hose it is the inner (main reservoir equalising hose). But later in it's career (after Lines West and most likely locotrol were abandoned) it carried a full set of hoses.


BLE Hogger
Can't speak about that specific unit, but there are occasions when you might see locomotives with anything from four to zero MU hoses on any particular end or side of the drawhead.

Some units just never get MUed due to various reasons such as all their mechanical servicing occurs @ their location and no need to move it to a servicing facility.

Another reason is sometimes the hoses simply pull completely out of the threaded nipple before the gladhands release and since there is usually MU hose redundancy on either side of the drawhead, it may be awhile before they get replaced (if ever).

It may simply be that your unit worked primarily as the leader and the hoses were unnecessary. Whenever it had problems and needed moved, it could have been MUed as the rearmost unit in the consist in a trailing position.

BTW, I haven't seen the fourth hose (Sanding) on locomotives for a long time now.

Tacoma Tom

New Member
You actually only need one side of the hoses so three would be the minimum. I have seen actually 5 on each side. I used to work as a hostler and it was extremely rare for those hoses to incur damages. I was actually disconnecting two locomotives and one of the hoses got hung up and it must have stretched 5 feet before it came loose! When it did it swung up and broke one of the ditch lights. If a hose does break it always breaks at the rubber and not at the nipple.

Not running any hoses is rather bizarre and uncommon. You wouldn't have any sand coming out of your trailing units which is pretty much a necessity. As a former locomotive mechanic I can only imagine they did it because the locomotive was on a dedicated flat route where it was probably a lone warrior rarely coupled to other locomotives. If they had a small yard and a small shop it would make sense to remove the hoses, dynamic brake grids. turbocharger, M/U receptacles and other parts that would keep maintenance to a minimum. Many short lines do the same thing to simplify the locomotive.

Knowing the Milwaukee road though and their program of "deferred maintenance" in the final years. I would have to imagine that sanders stopped working and needed work. But rather than fixing the problem they simply removed the sanding hoses and capped the plugs which would satisfy the FRA requirements. The unit would likely always be the last trailing unit in the consist.

If the same locomotive had some sort of control stand problem with the deferred maintenance program, then the seats would likely have been removed, radio and horn lever removed, and the unit classified as a booster unit only.


New Member
Looks like the couple of photos I have of it missing most of its' MU hoses may have been taken of the same train, or within a short time of each other. The 2-digit road number SD40-2's were locotrol equipped, and the 21 was a master. I imagine it spent most of it's time in the lead, with non-locotrol units trailing, and a 2-digit remote and non-locotrol running as a helper. So it if did somehow lose one or more of it's hoses, it wasn't an emergency. All other photos show a full set (4 on each side).

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