David Soderblom asks:
An obvious question: why were the tank cars cleaned? The need isYou're right that cars carrying the same thing over and over weren't
cleaned unless they required tank repairs of some sort. But many tank cars
were operated on short term leases and the commodities they carried changed
fairly often. In the case of such loads as motor fuels, lubricating oils,
etc. even a little contamination from previous loads was unacceptable.
Richard H. Hendrickson
Ashland, Oregon 97520