Apart from UTLX which US Tanker car and other freight car leasing companies have been around since the 1940's? Obviously I've Googled this but so far I've failed to find a site that has a complete history? Not expecting anyone to do my surfing for me but if anyone knows of any comprehensive site links I'd appreciate the links

My main interest is in what was in use, and where during the period 1945-1975. Obviously the file library is full of tanker cars but knowing what ran where and when is what I'm after.

Also did pre-WWII tank cars stay in operation long after 1945? ....and if not was there a specific reason?

Thanks in advance for any help.