locked Re: Authorization for Car Assignment (ACA)

D. Scott Chatfield

Since Trailer Train's intermodal cars have always been stenciled for restricted loading only, I would not read "return to general service" as returning cars to intermodal service, but to regular flat car service as AAR type FMS with reporting marks JTTX.  Then they could be used for long loads like pipe until they rebodied them for wide body racks.

While Trailer Train did have low-deck flats in piggyback service back then, the LTTX 500000 series, they were not quite the same carbodies as their thousands of low-deck rack flats.  Autoracks can be assumed to be carrying an equally distributed load on their decks.  A trailer flat, most definitely not.  Indeed, autoracks are the one North American freight car type where the car weighs more than its load.

Also, LTTXs did not have end-of-car cushioning, which was true of all of Trailer Train's trailer-only flats.  The cushioning was built into their hitches, which weighed a _lot_ less than an EOCC unit.

It would interesting to read the context of this "Return to General Service" in earlier memos, but from my professional experience in intermodal and the evidence that the above referenced KTTX went right back into autorack service, I cannot imagine that it was ever intended to mean "release for intermodal service," at least not in 1978 and for those classes.

Now if you want to sit through a clinic on the 1980's Twin-45 program, I can give you a blow-by-blow account of rack flats that were converted to pig flats and vice versa.  It was dizzying.....

Scott Chatfield
Formerly of the Southern's intermodal department 

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