NYC C1a for UP829

[feltonhill]

I located the book you referenced which had more info than the sketch in Trains mag. Thanks for the info!

The drawing is dated 3/28/45. The Niagara test report was dated 7/3/48. Tests with 6023 were run 6/46 to 11/46. Tessts with 5500 were run 6/47 to 11/47. As you can see, the tests were run after the C1a sketch was made. It was probably one of the considerations that came out of the design process for the Niagaras and Central's awareness of PRR's activity with the T1's.

I have no "official" perfromance estimates for the C1a. I ran some of my own figures to see what if may have done. I assumed the same boiler as a standard Niagara, but with the increased 290 psi pressure noted on the sketch.

In regular service, it would have been only a slight improvement over the Niagara as far as fuel and water economy is concerned. It would have had a higher DBHP output at speeds above 70 mph due to the improved steam distribution of four small cylinders. However, considering how conservatively the Niagaras were designed with respect to tractive effort and adhesion, the C1a would have been harder to handle under the usually-found variable rail conditions on most railroads. A pair of jointly controlled two axle engine sets is touchier than one directly controlled four axle engine. Baker valve gear may have helped because poppet valves could reduce back pressure to the point that there was little to help arrest a slip once it occurred (other than shutting the throttle and waiting until everything settled back down). IMO Central was wise not to bother with the C1a.

[Anonymous]

Thanks for the follow-up. It may have been a case of "PRR has one.." or proposed as an alternative to diesels by NYC or Alco. In any case the Century - Broadway race out of Englewood became an E7 vs. T1 affair. The E7s must have won, since PRR went to them as well.