The Steam Railroading Institute’s auxiliary water tank car is the tender from a Chicago, Rock Island and Pacific 5000-series 4-8-4 steam locomotive, built by the American Locomotive Company in Schenectady, New York.  In the 1950’s, the Rock Island converted many of these tenders to movable diesel-fuel tank cars for branch-line terminals.  This car was sold to steam locomotive collector, Dick Jensen of Chicago, and resold to a steel mill for fuel storage at Lemont, Illinois.  It was purchased by Steam Railroading Institute member, Aarne Frobom and donated to SRI for use behind Pere Marquette 1225 on longer trips. It has an approximate water capacity of 30,000 gallons.