In the September 1945 issue of Along the Line, the New Haven Railroad employee magazine, there's a one page quiz ("What Do You Know?") with about a half-dozen pictures of railroad items to see what you know. All were pretty easy for somebody with some knowledge of a railroad.
But this one was interesting and useful:
I already knew what New Haven mile markers looked like (although it is possible that there are other options, since the NH was made up of so many predecessor roads and there are differences on each line). The same applies to speed limit signs. But I wasn't entirely sure about the other two options.
I guessed correctly, and now I have another prototype detail that I can add that will also assist my operators - it's indicating how many cars the siding will hold to that point. It's such a simple detail to add but will be extremely helpful to the crews when working Track #5 which is where I'll use these signs.
While I don't have any more details as to how these were used, I'll use it on Track #5 between streets. For example, the number of cars from the start of Track #5 to East Main St, and then the number from East Main St.to Elm St. It will be particularly helpful at the start of Track #5, because I can also use it to mark the start of where a car can be safely left without risking it rolling down the grade into the helix.
Unfortunately, this appears to be the only issue that had this sort of quiz.