General American made 250 tank cars for Santa Fe diesel service in 1949, TK-N. They were near duplicates of the TK-Ms except that both tanks and underframes were entirely welded. In mid 1953 Santa Fe took delivery of 200 more cars, identical to the TK-N, and called them TK-O. The only difference was anti-skid strips applied to the top of the TK-O tank on either side of the dome to provide more secure footing for workmen.
The Precision Scale Brass 16,000 gallon tank car is a reasonable stand-in for a TK-N or TK-O tank car. It is 16" too long which will make it stand out when put next to a Pecos River correct version, but you can purchase 3 of the PC cars for the cost of a Pecos River. The other weaknesses are the very poor turned brass fittings on top of the dome. It is a compromise for economy.
Precision minimal underbody
Pecos River vs Precision Scale
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