Nostalgia & History > Southern Railway SD45s as DPUs in 1970

The morning of April 29, 1970 was foggy in Potomac Yard (Alexandria, Virginia). From the bridge that crossed the middle of the yard I found 2 new Southern SD45s mid-train with a radio car (a boxcar red boxy car) with antennae on its roof. My guess is instead of making many diesels capable of receiving DPU instructions, Southern created a much smaller number of radio signal receiver cars that then talked to the DPUs through a MU cable. I sure could be wrong on that, so I'm hoping someone with knowledge instead of a guess chimes in. For the TO search engine, the units in the scans are 905912, 3069, 6311, 3167, and 3163.


Comments welcome.
Enjoy,
Marty Bernard



Edited 2 time(s). Last edit at 11/26/14 20:15 by MartyBernard.

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Nice photos Marty. The white number boards represented SR units that could lead on trains with remote control units mid-train. It was always impressive to see those trains back then, especially to this, then roughly 10 year old kid. I did not see them often as I grew up on the east end of the Georgia Railroad, however when I did encounter them at my paternal grandparents home in Waynesboro, GA or while visiting the mountains it was always amazed. That was pretty high tech back then.

I remember a very short blurb written years ago by a truck driver waiting at a crossing for a Southern Railway train in Trains magazine. The whole story was about the power of the units then more coming later in the train.

Jay

Marty,

You are correct about the receiver cars. Placing the receiving equipment in the receiver car allowed any locomotive to be used as a DPU. Also the electronics of that era took up a lot more room than modern DPU electronics and there was plenty of room in receiver car.

Keep the Southern photos coming!

Charlie

MartyBernard Wrote:
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> The morning of April 29, 1970 was foggy in Potomac
> Yard (Alexandria, Virginia). From the bridge that
> crossed the middle of the yard I found 2 new
> Southern SD45s mid-train with a radio car (a
> boxcar red boxy car) with antennae on its roof.
> My guess is instead of making many diesels capable
> of receiving DPU instructions, Southern created a
> much smaller number of radio signal receiver cars
> that then talked to the DPUs through a MU cable.
> I sure could be wrong on that, so I'm hoping
> someone with knowledge instead of a guess chimes
> in. For the TO search engine, the units in the
> scans are 905912, 3069, 6311, 3167, and 3163.
>
>
> Comments welcome.
> Enjoy,
> Marty Bernard

DPU - there was no such terminology in 1970.

This was "Locotrol", a locomotive "radio based" communication system, that converted (head end) engineer manual control selections (including both power and dynamic braking), to outgoing radio signals, via equipment in the nose. Locomotives so equipped were referred to as "Masters". These signals would then be picked up by an UNMANNED "receiver car" (or, later on, locomotive), and further converted to m.u. commands on the helper.

GN and Southern were the earliest users of Locotrol, followed by the CP, Santa Fe, N&W, UP, NP, BN, and finally SP. If I left out one or two, please feel free to add them.

Bob

ATSF100WEST......Out

Southern locomotives equipped to lead "radio trains" had white number boards with black letters, instead of the usual black number boards with white letters.

KCS south of Pittsburg.

Milwaukee Road air brake rule books mentioned "Locotrol".

not DPU`s , they were called mid train slave units back then

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British Columbia Railway (BCR / BC Rail) had Locotrol in the early 1970's. It was Locotrol 1 and then Locotrol 2 then to DPU terminology. Early we used converted B units for the receiver cars, called RCC, remote control car. Attached image of lead loco locotrol panel, sorry not very good image. Doug

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More info on the purpose-built radio control cars at http://www.trainlife.com/articles/536/add-a-radio-control-car-and-helpers-to-your-southern-consist

Photo #3 with SD-45s, a SD-35 and a SD-24 is great! Interesting series...

James Nelson
Thornton, CO
www.flickr.com/mojaveflyer

Image of a BCR RCC control car, converted B unit. The RCC had been gutted out and the radios and and air brake equipment was installed for locotrol operation. All hoses connected between the car and units as well as MU jumper cable. Also a cable was plugged in from the diesel unit to power the electronics on the RCC units. Some of the RCC's had a company radio, bunk, hot plate and oil heater. Also another image of the Locotrol console, and view of the newer Locotrol 2 airbrake buttons. Locotrol 1 had four pushbuttons above the brake valve (can't find image) button to apply air brakes, release and two for the independant apply & release. Also in the third image you can see the headlight switches, please note the toggle switch for "ditchlights and corner lights." Doug



Edited 1 time(s). Last edit at 11/27/14 08:32 by hoggerdoug.

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M Wrote:
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> not DPU`s , they were called mid train slave
> units back then


Correct. Later, because of the "master/slave" terminology, it was
changed to "master/receiver."

The Milwaukee did use Locotrol through the Montana Rockies IIRC. However,
it was gradually phased out in the 80's due to operational issues. BN made
a huge investment in it in the mid-70's, but had dumped it by 1980. By 1990,
only the Santa Fe still used it. Then, GE/Harris came up with new hardware/software/both
for what is now DPU technology and, as they say, the rest is history.

Thanks, Marty, for the look back, and to all the others for the additional shots.

Nick Tharalson,
Marion, IA