Trying to identify old 2x4 plate Another odd-ball in my endless sorting and cleaning: a basic 2x4 black plate, but with two raised hollow tubes, larger than a stud. No part number. Here's a picture of it:
This 2x4 plate belongs to the 


housing of an old 4.5V train motor. 






There are some scratches on the edge of your plate, most likely from an attempt to pry it off with a screwdriver.