Ben Hom wrote:

During the early 1950s, the Santa Fe
rebuilt the ice hatches on SFRD reefers to better accommodate crushed icing,
changing the arrangement from the hatches opening towards the ends of the
car with stops keeping open hatches in a vertical position to the hatches
opening towards the center of the car to lie flat against the roof.

The reason, as I'm sure Ben knows, but doesn't say clearly, was the introduction of icing machines, which passed over the car roof, and would have been interfered by hatches standing vertically.

Tony Thompson Editor, Signature Press, Berkeley, CA
2942 Linden Ave., Berkeley, CA 94705 www.signaturepress.com
(510) 540-6538; fax, (510) 540-1937; e-mail, thompson@...
Publishers of books on railroad history