Note that "do not hump" signs don't necessarily mean a car didn't go over the hump. With the advent of "electronic yards" in the late 50's when computer control of retarders was introduced, hump yards had much better control of car speeds. On the NYC we ignored those placards at the new yards because it was thought that there was less risk of unacceptable coupling speed than in a flat yard.

Malcolm Laughlin, Editor 617-489-4383
New England Rail Shipper Directories
19 Holden Road, Belmont, MA 02478