If you model the steam era, you need one of these water tanks, with pumphouse. This design was built all over the Great Northern from 1915 to the end of steam. This is a model of a common part of the railroad scene in the steam era and it takes very little room. This model includes the pumphouse that protected the gasoline powered water pump that was typically used to keep the tank full.
Because of its height, keep it away from edges and aisles to reduce the chance of inadvertently snagging it.