Nostalgia & History > Could a Diesel Hydraulic Be MU'd With a Diesel Electric?

Diesel hydraulics seem to be a popular today as there have been two threads on the topic.
So I thought I would start a third thread. I would like to know if diesel hydraulic locomotives
could be MU'd with diesel electric locomotives. My guess is that it would not work because they
are fundamentally different machines. However, I would really like to know the facts. Thanks much.
ALLEN

If you look at photobob's Bayshore photo you will notice the front of the KM has a standard diesel mu plug, a battery cable plug and a full set of 26 air hoses.

SP ran the KM's with EMD units all the time. Sometimes as lead units or trailing. No problem.

> a battery cable plug

Probably field loop connection, which resembles a battery cable.

Coming into Roseville Yard at Antelope.

Robert Morris Photography
http://www.snowcrest.net/photobob/index.html

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Thanks for the responses.
I should not really be surprised that diesel hydraulics and diesel electrics could be MU'd considering that the Milwaukee Road MU'd diesels to their Little Joes.
ALLEN

Many of the KMs I saw in the central valley were MU'd with an F7B. Got one in Oakland behind an Alco C628.

krm152 Wrote:
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> Thanks for the responses.
> I should not really be surprised that diesel
> hydraulics and diesel electrics could be MU'd
> considering that the Milwaukee Road MU'd diesels
> to their Little Joes.
> ALLEN

The Milwaukee did not MU their electrics with diesels in the same sense as diesels MU with other diesels.

A diesel could not be used as a lead unit to control electrics in consist. The Little Joes (and certain of the box cabs) had to be used as the lead unit, as they had an auxiliary throttle which controlled trailing diesels. The Joes throttle had 37 control points (plus off), while the auxiliary throttle had 8 points, corresponding to the standard diesel throttle. The two throttles could be used independently, or could be mechanically interlocked so that operation of the Joes throttle also moved the auxiliary.

-John

On the subject of mu'ing, could f-mt trainmasters mu to other locomotives i.e. Emd or alco? Also could go-1 mu to diesels? Thanks Sam

Factory equipped, most manufacturers' [Edit: add "early"] units did not readily MU with other makes, but home-made or aftermarket jumper cables helped resolve that problem. As time went by, PG governors, 27 pin cables, electric sand control, and elimination of field loop dynamic brake control standardized this. Then the only engines which would not readily MU with other makes had no MU cables and hoses, a mechanical throttle, or Baldwin pneumatic control.

At first, some brake systems did not play well with others, but this was eventually standardized, as well.

-LD



Edited 1 time(s). Last edit at 02/19/18 09:29 by LarryDoyle.

I took this photo of Alcohaulic 9152 w/ F7 6315 at San Jose waiting for another run over the Altamont back when you could have bought that Caddy for about 400 bucks.

Ed

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hogheaded Wrote:
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> I took this photo of Alcohaulic 9152 w/ F7 6315 at
> San Jose waiting for another run over the Altamont
> back when you could have bought that Caddy for
> about 400 bucks.
>
> Ed

I did buy a 57 Caddy convertable in 67 for $350. Wished I kept it.
Chris

Anything is MU-able with anything else provided diesel engine control and the air brakes work in harmony with each other. What occurs between the diesel engine and the drive wheels doesn't matter as long as output is more or less matched between units.

EMD, Alco, and GE units have always been MU-able provided they used the Lemp/GE system of solenoid-controlled governor and load regulator because GE developed it for EMC in the 1920s. EMC/EMD, ALCO, and GE all used the same system. Baldwin used air throttles, which were incompatible. Not sure about F-M.

Since there are pictures of the hydraulics running around with "standard" diesels, it's a safe assumption that the diesel engine and brake controls were the same, the difference being the method of power transmission from the engine to the wheels.

> At first, some brake systems did not play well with others, but this was eventually standardized, as well.

The #6 system -6-ET and 14-EL- can be MUed provided each locomotive is also equipped with a transfer valve and an equalizing pipe to the next unit. 24-RL and 26-L are fully compatible with each other but not with the #6 system. 8-ET/8-EL are closer to the #6 system with regard to MU-ability. Only the #6 and 26-L systems are in current production. No info on the #22 system.

EtoinShrdlu Wrote:
-------------------------------------------------------
> EMD, Alco, and GE units have always been MU-able
> provided they used the Lemp/GE system of
> solenoid-controlled governor and load regulator
> because GE developed it for EMC in the 1920s.
> EMC/EMD, ALCO, and GE all used the same system.
> Baldwin used air throttles, which were
> incompatible. Not sure about F-M.

Today a standard round 27 point receptacle is used.

EMC/EMD has used round receptacles, for like, forever. But not always the same ones. Originally, sand control was pneumatic. 16 point, and 17 point were used in the early days, and Union Pacific used a two cable system for awhile - one cable was 12 point and one was 21 point.

FM had an oblong 12 point connector in their early engines, which had pneumatic control.

Alco had a round 17 point, but not the same pinouts as the 17 point EMD.

Not sure there is an exact date, but after about 1960 or so they became pretty much standardized.

As noted, Baldwin used pneumatic control with a 16 point cable to control lighting, etc., that was different than EMD's 16 point.

-John



Edited 3 time(s). Last edit at 02/19/18 13:54 by LarryDoyle.

Southern Pacific's series KM's had a unique MU setup in that they could MU trailing dynamic brakes controlled by either point potential or field loop.

Howard