Taken from a Q&A series on a web forum
Q) Was there that much difference in the performance of a centrifugal vs. reciprocating pump in the feedwater system?
A) It was only on the 2900 series that you had this problem. These engines carried 225lbs pressure and once you lost 15lbs, you usually were starting to have trouble with the fire. For some reason these pumps were very sensitive to the boiler pressure below 210lbs. Fire problems were usually caused by a change in the coal. You would be going along and the fire would be doing just fine, and suddenly the coal would change. The company used coal from the strip mines in southern Indiana and we called it Indiana real estate. There wasn't any way for you to know the coal was going to change until all at once the fire started burning a dull red and the boiler pressure started dropping. Now, you had to increase the stoker speed for more coal and forget about the smoke and see if you can hold the pressure and check the depth of the fire. With this dirt coal you have to keep a thin fire to make it burn. You will have to rock the grates, not shake them to get your fire the right depth. In fact, I have left the grates slightly cocked with this coal to get all of draft I could to make it burn. All of the 2900's that I fired had this problem, some more than others. I don't know if these pumps were a little under sized or what but the reciprocating pumps never gave problems unless they needed repairs.
Q) If the boiler pressure (steam) dropped, wouldn't that in turn lower the resistance that the pump had to overcome to force water into the boiler? I know I'm missing something here in trying to understand exactly how all these processes are related to each other.
A) I never could find out why this pump acted in this manner. I have been telling what took place but not all
of the actions. When the steam pressure was 210-215lbs the pump would supply the boiler and if you opened the steam valve it would supply more water than the loco was using. This is as it should be if the pump is normal. The problem was, as the steam pressure dropped below 210, it seemed as if the pump slowed down more and at 200lb the pump even though the control valve to the pump was wide open would not supply the boiler. It was as if for every 1lb of steam you lost you would lose 3lb to the pump and the pump would slow down, the pressure acting as a governor. The 2800 L-2 had coffin feed water heaters and used a centrifugal pump but did not have this underpumping problem. All pumps would slow down as the steam pressure dropped but not to this extreme. Also this slow down did not start until the steam pressure was below 195lbs on all of the other pumps. As you say all things being equal you should have been able to supply the boiler down to about 180lbs.and you could except with the one pump. I don't know if all 2900s had this problem, but the several that I fired did. In fact there was a point if you were trading water for steam, forget the pump and use the injector.
Q) I have heard that the 2800's were better engines than the 2900's, but I didn't know why...
A) When you had this water supply problem and after every thing was back to normal you took it in stride and accepted this flaw on these engines, always ready when working on these engines. If there had been 2 or 3 boiler explosions and someone had survived to tell the story something may have been done. If you reported the pump they would have tested with 220 lbs. boiler pressure and would OK the pump. The engineer or myself would have to hold their hand and make sure the pressure was 195lbs, and when it showed it was not supplying the boiler they would say use the injector that's what it is on there for. So the problem was never admitted to exist.
As with everything else, without the word EXCEPT, the world as we know it could not function. Some of the L-3s
had Elesco feed water heaters and the same water pump as the 2900s. I don't remember having any water problems with these engines. Of course they may have recognized the problem as used on the 2900s and corrected this on the 303?. I can't believe it was anything more than a larger supply pipe from the turrent to the pump.
Maurice worked the Michigan Division from 1947-1981. He then worked on the Bee Line from 1981-1992. From 1947 until august 1950, he worked on the section at Shirley and Markleville. In 1950 he started firing on steam and then on through the diesels. Maurice said, "I had the pleasure of working with C. C. Staley and Ron Buser many times."