Re: coffin feedwater pump

I am not where I can acess any manuals, but my recollection of some of the systems I have seen in the old ICS books is that it may be a turbine pump. Steam turbine driven, but also the pumping end may be a turbine design rather than a centrifugal pump. They look similar, but in stationary service for boiler water feed I have worked on electric motor driven turbine pumps. A 1 stage (one impeller) centrifugal pump is typically not capable of creating efficeintly the high pressure needed for high pressure boiler water feed. The turbine impeller design on the pumping end has vanes that run very close to their adjacent surfaces and is capable of high pressures. I was thinking that the Worthington system on locomotives uses a pump of this type I believe to pump water from the tender to the feed water heater, then uses a compound recirocating steam pump to force the heated water into the boiler. I think 844 has this system. Maybe Rick Steele can shed light on this.