Q: When I was looking at pictures of the Milwaukee, Racine & Troy locomotive fleet, I noticed small numbers near the herald on some diesels. Were those numbers tied to the control system used on the layout, or did they have another meaning? — Jason Trew
A: Those single- and double-digit numbers near the herald on MR&T diesels corresponded to the Power Systems Inc. Dynatrol command control system that was used on the club layout. In the December 1989 Model Railroader, longtime staff member Jim Kelly wrote, “One other very important development came in the early ’80s. It was obvious that if the MR&T were to become an operating railroad we needed to be able to run more than one train at a time! We had begun wiring rotary switches and harnesses for six-cab block control, but the task looked absolutely hopeless given our lack of manpower and zero enthusiasm for wiring.
“You may remember that commercial command control systems came of age in the early ’80s — this development came to our rescue like cavalry charging over the hill in an old movie. We purchased PSI’s Dynatrol system and voila! — finally we could run multiple trains simultaneously.”
I recently e-mailed Jim to learn more about the significance of the numbers. He replied, “With the Dynatrol system you could control up to 16 different locomotives with numbered red plugs about an inch long that were plugged into the controllers. A receiver could respond only to a controller fitted with the plug numbered for its signal. The small number on the cab indicated the number for the receiver inside and the plug required to run it.”
When the layout was switched to Digital Command Control, some of the MR&T diesels had the Dynatrol equipment replaced with decoders. The small numbers were painted over on those locomotives.
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