I’ve seen pics of just about every type of loco together in a consist. Even steam with a GP or SD. I figure with those you have to have a crew in each cab. But what about things like old diesels and new computerized locos? How does a brand new loco tell a 40 year old loco how to run? Can a diesel MU with an all electric commuter loco?
I recall that there were MU compatibility issues between early diesels made by different manufacturers. (IIRC, Baldwins, as built, could not be MUed with Alcos and EMDs.) What’s more, some diesels purchased for specific uses, were not built with MU equipment, but often had it retrofitted during later visits to the shop.
I think MU capability has been standardized since initial dieselization.
There is a big difference between a double, triple head (two or three locomotives working together) and an MU. MU implies the locomotives are “wired” together with one cab controlling the rest of the locomotives. True MUs on diesels were not standardized for several years. The UP steam locomotives are not MUed with their support Diesels there is a crew in each loco.
Many switch engines and smaller diesels weren’t equipped with MU capability so couldn’t MU.
Most Baldwin locomotives (but not all) were equipped with an air operated throttle and so coupldn’t MU with any other make of diesel because they had electric throttles. Up into the 1960’s there were a couple different arrangements of MU electrical connections so some railroads’ engines wouldn’t MU with other railroads’ engines.
Other than that they pretty much all can MU. Some combinations are better than others, but they can all basically MU.
Dave H.
Thanks guys! That about answered it. I was wondering how the other throttles were controlled from the master. Whether it was air, hydraulic or electric.
I know that NJTs equipment can all be MUed because a Cab Car is basically an MU control point.
This includes: GP40 (all types), F40PH, U34CH (no longer in use), PL42AC, ALP-44 and ALP-46 (both ALP locos are electric). I’m not sure about NJTs Aroow MU cars.
Also, it was kinda up to the railroads whether they wanted to order the engines with M.U. connections and such or not. Soo Line’s Baldwin AS-16’s couldn’t be M.U.'ed with anything…even with each other. That’s the way Soo Line wanted it. I think Minneapolis and St.Louis RS-1’s weren’t set up to M.U. either??
In the early days of diesels, railroads bought diesels to replace specific engines for specific jobs, so they might buy say an RS-3 to take over a branchline freight run normally pulled by a 2-8-0. If the RS-3 could do the job by itself, the railroad figured why pay the extra money to have the M.U. capability built into it, if it wouldn’t be used. Plus, in the early days, if they needed more power, they would buy a bigger engine, or a multiple unit, like say an A-B set of F units with a drawbar between the two, so they were essentially one two-section locomotive.
Of course, many railroads added M.U. capability to engines over time too, when they realized the limitations not having it created.
Unless the railroad took the expense of rewiring them the FT locomotives could only MU with each other and with F2s that were specifically built with the FT wiring.
Of course a lot of the very early locomotives could not MU or could only MU with a very small number of similar locomotives. These include the ALCO-GE-IR boxcabs and switchers, all of the Westinghouse diesels, the locomotives made by Mack and by Brill. The Baldwin demonstrators 58501 from 1925 and 61000 from 1929 were provided with MU but each was a unique system. The locomotives that were designed by New York Central and built in the 1920s were provided with MU but the depression removed the possibility of building more so each of the three was unique. And the diesel/gas switchers that the Pennsylvania Railroad built for itself could only MU with themselves.
Jerry Pinkepank wrote an article for the December 1968 TRAINS that provides a short history and background of the development of MU control for diesel locomotives.