Most everything I've seen on this subject indicates that hatch covers
were kept in the closed position unless ventilation was required for
the load. Certainly there were directives on the Santa Fe to keep
the hatch covers closed when the cars were in storage or used for
braking on Cajon Pass so the interiors would stay clean.

There is an official exception, however. The June 1954 Santa Fe
Circular No. 11, uncover by Keith Jordan, has an interesting bit of
information that provides the exception to the rule for the position
of hatch covers on produce reefers in citrus service.

The circular says:

"(a)SFRD cars moving west empty should have hatch covers raised to
permit old ice to melt."

The complete circular is posted in the Files Section of the Citrus
Industry Modeling Group.

Bob Chaparro
Moderator
Citrus Industry Modeling Group
http://groups.yahoo.com/group/citrusmodeling/