According to http://www.nakina.net/other/report/reportd.html

the DOX reporting marks were used as follows


DOX

The Derby Oil Co.

8/1920-7/1937


DOX

General American Transportation Corp.

4/1938


DOX

Derby Oil Co.

1/1950-7/1954; eliminated 4/1955


DOX

Derby Refining Co.

added 4/1955; 10/1957; eliminated 1/1960



Note the change to GATC which is similar to the action of a number of oil
companies in the 30's as they sold their tank car fleets and switched to
lease agreements. This would indicated that Derby also sold their tank cars
in 37/38. Then beginning in 1950 Derby again claimed ownership of the
reporting marks, and changed their corporate name in 1955.



It would appear that Ted's research was not complete. And it further
highlights the difficulty of using the ORER to track private owned cars, esp
tank cars.



Doug Harding

www.iowacentralrr.org