Earl:
Except for the UP and SP, I don't know what other railroads displayed train numbers on the engine. Do you know of any?
Also, a number of railroads tried different ways to display engine numbers--L&N painting the number on the lense of the headlight comes to mind. I wonder if this is the reason the Grande had number boards--for better identification on meets, etc. And that brings up another question concerning train orders. How would the dispatcher have listed the San Juan (any regular train) on a meet order?
Les Clark