Tim Gilbert has previously posted the January 1943 numbers for
privately owned tank car fleets of 1000 cars or more

Tim, we are indebted to you for presenting all this statistical
analysis.

Your comments about "petroleum" tank cars versus other tank cars is
interesting. I think the majority of WWII era tank cars were used
for petroleum products. Few tank car loads can tolerate being
contaminated with something else - few except for crude oil,
gasoline, kerosene, diesel fuel, aviation fuel.....

Consider trying to clean a tank car out. Rinse it with water? Even
with a fire hose it would take a long time. Discharge that water by
gravity - longer still. Then what do you do with 1000s of gallons of
contaminated water? Rinse it with solvent? Now you have 100s or
1000s of gallons of dirty solvent.

Someone pointed out that oil refineries cleaned out tank cars with
steam. This was probably cars used to haul crude oil. The heat
melted solds like paraffin and bitumen. Some of the steam condensed
and the melted solids, condensate other solid crud in the car like
drilling mud and sand fall to the bottom. Open up the bottom valve
and the pressure blows most of that stuff out.

Many other types of tank car loads would find the little bit of
water that remains as objectionable as a previous load. Even a
little bit of water in gasoline is objectionable. Remember when the
fuel line froze in your car?

Many chemical tank cars were made special, expensive materials.
Using those cars for crude oil would mean the car had to be cleaned
out before it's intended load could be hauled again. Too, how would
you know which chemical tank cars were clean and suitable for the
intended loads?

Ed