Pictures of steam builder erecting shops often show a large row of locos under construction. How many locos could Alco, Baldwin, or Lima build at one time? How long did it take to build a steam loco and about how many could they turn out in a year? What about EMD during the 50s & 60s? GE now?
I don’t know about steam production, but EMD at La Grange could turn out about 2 or 3 locomotives a day at peak production. GE is probably similar.
I think steam production capacity is going to be almost impossible to adequately define… Talking off the top of my head (many people tell me I have a point there), I would think it would depend on what size locomotives were being built-the differences between, say, a SW1 vs E7 would be much fewer (from an assembly standpoint) than the differences between an 0-4-0 and 2-8-8-4.