Re: coffin feedwater pump

The Coffin system was fairly common on the Union Pacific. It was applied to a number of 2-10-2s and 2-8-8-0s. From the operational standpoint, they were very simple having one valve to control the centrifugal pump--turbine unit located under the left side of the cab. There was an in cab gauge that alerted you to the fact that you were or were not injecting water based on whether the pressure exceeded boiler pressure. Most of the Coffin unit was not very visible as in entailed a large bundle of heater pipes arched around the smoke box. This accounted for the extra long smoke boxes seen on locomotives with the system. Also, a close examination of the outside of the smoke box will reveal the sheet metal covering over the heater pipes imbedded in the smoke box.
Les Clark