I'm working on an exhibit, and also have general curiosity regardless, what are the advantages/disadvantages of horizontal and vertical boilers for permanent static (as in factor) v. locomotive use?

Obviously, height and capacity would be a limiting factor for a vertical boiler used with a locomotive.

Joshua

One of the collateral advantages of a vertical fire tube (VFT) boiler is the steam above the disengagement (top of the water) line is superheated a little producing a dryer steam with a little more energy. A VFT is probably one of the most inexpensive configurations to build making them very popular for small to medium industrial applications where height was not a concern. The vertical boiler configuration is still used today in fire tube and water tube designs for generating steam and hot water.

When the boiler is under steam, the steam actually cools the upper dry portion of the tubes. This effect is not in-play when there is no steam present, i.e. firing up from cold.
Therefore, a boiler of this type should not be pushed excessively when firing-up.