This kit represents the standard steel water tank that was developed by Chicago Bridge and Iron for the railroad industry. Installations were done from the late 1800's to the end of the steam era with many still in use today! The kit allows you to build either the 100,000 gallom (2 courses) or the 125,000 gallon (3 courses) version.In addition we supply 2 tops, 2 bottoms and 2 beam lengths so any common variant can be modeled. Our standard Fairbanks Morse water column is also included! Easy to assemble! 4" in diameter and 6-9" high. Very nice!