Scott,

The R.C. models are based on 6 orders of cars with a relatively-new (at the time) ACF welded underframe. The prototype cars had 60”-diameter x 22” domes. There were some subtle differences in the 6 groups, but all of them were of the same basic dimensions. 

Lot 3385 - SL-SF 191000-191129, 130 cars built ca. 8-49, last 30 cars heater pipes

Lot 3401 - USAX 11900-12099, 200 cars built ca. 9-49

Lot 3417 - USAX 11690-11899, 210 cars built ca. 5-49

Lot 3559 - KPCX 2500-2522, 23 cars built 7-51 (Koppers Co.)

Lot 3639 - SHPX 16754-16773, 20 cars built 1-52, heater pipes (leased to Bakelite Company)

Lot 3687 - JTBX 17-18, 2 cars built 4-52 (J.T. Baker Chemical Co., Taylor Chemical Division)

Similar cars built from 1953-1955 had at least some different dimensions & others I’m unable to locate drawings and/or photos to verify them as being the same as the model.

SUNX 6467 isn’t listed in the 1955 tank car tariff book, which is the closest date I have. 

Regards,

Ed Hawkins