What was inside a radio car; are there pictures of this equip.?

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I have read several questions pertaining to the mid-train "relay" or "radio" cars. I understand that they contained some type of remote control equipment for operating mid-train locomotives from the lead locomotive. I am interested in finding out about the equipment inside the cars. I would appreciate any information directing me to sources which might include interior photographs or drawings. I would also like to know (generally) how the equipment in the car functioned to run the un-manned mid-train locomotives. Thanks.

-- John M. Painter (paintj1@juno.com), May 01, 2001


Over the roughly 35 years they were in operation, the SR radio cars varied in type of contents due to advancing technology. Originally there were racks of magnetic relays inside, and these were later replaced by smaller components. There were the radio transmission power packs inside. There was a brakestand inside that controlled the slave engine's brakes via the standard MU setup. This part is what I, as an engineer, would have to manually cut in or out at times. There were other large electrical boxes in there unknown to me, concrete weighting, and I think a fire extinguisher. Not all the cars were alike. Some could control both SR and N&W Locotrol types. Also at one time SR had a setup to control two sets of slaves from the master engine. As for operation, the master engines talked to the radio control cars on assigned radio channels. Each master engine had its own address code that had to be set in the radio car, and the train direction switches had to be set. When the radio equipment was activated and continuity was established, you used electo-pneumatic brake buttons instead of the standard brakestand in the master engine. This and the throttle changes, reverser changes, and other commands and reset functions were transmitted to the radio car which was mu-ed in standard fashion to the slaves. Continuity signals were continually sent back and forth. The engineer had a basic monitor panel for the slave operation which also housed the slave MU switch, the remote sander switch, the remote feedvalve cutout, the alarm, and the other reset switches. Southern developed what became know as Locotrol inhouse. Even after it was licensed out for use on other roads, SR continued to refine their original system. It worked well as long as it was maintained well, and it was the best in the industry. Southern radio trains were a unique treat to run. Properly made up a long radio train handled well and was responsive. Unlike other railroads, Southern utilized radio operations for speeding up operations on some of it's hottest fast freights, partically First 153- the Southern Flash. In later days, NS ran some extra long pig trains with radio power too. The few key people who developed and maintained the radio cars and engines have retired, but the memories of fine radio operations and innovation remain.

Ben Lee

-- Ben Lee (Bengineer7@aol.com), May 05, 2001.

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