speed and cutoff

[nw-mailing-list at nwhs.org]

This does not add any information that John Rhodes was seeking, but it is a little bit of lore from a half century ago.

My first summer job with the railroad was in the N & W's steam locomotive shop in Durham, NC, where the foreman at that time was W. D. (Bill) Emmons (whose father was an N & W roadmaster, at Ft. Gay, WV).  Bill was a great raconteur, and he enjoyed recounting railroad stories (a closet railfan?).

One story pertaining to cutoff was about the reaction of some of the "old head" engineers when the N & W first installed back-pressure gauges on most of the road steam locomotives to guide the engineers in adjusting the cutoff for the most efficient operation (least back pressure in the cylinders).  He said that old engineers snorted that they did not need the gauge to tell them what to do.  They said that all they had to do was to listen to the sound at the exhaust stack to tell them when the old girl was running "right."

Gordon Hamilton
  ----- Original Message ----- 
  From: nw-mailing-list at nwhs.org 
  To: NW Mailing List 
  Sent: Saturday, January 14, 2006 2:35 PM
  Subject: Re: speed and cutoff


  John,

  Finally, I got some of the information I think you are asking for. This I have from Test Engineer Robert M. Pilcher, who did most of the testing on the late steam era locomotives. There is nothing I have about the S1/S1a and I have seen nothing about a dynamometer car being used on a switch engine.

  Mr. Pilcher's notes to me are as follows:

  1.    The early/older Y's usually were worked at about 70% cutoff and the throttle then worked to increase or decrease power as needed once the 70% was reached. At maximum drawbar HP the speed would have been at about 15 MPH for the Y3/Y4 and 20 MPH for the as built Y5/Y6/Y6a.

  2.    The Y6b's [later included the improved Y5 and Y6's] were worked at about 55% cutoff before the engineer regulated power needs by the throttle. The maximum DBHP of 5600 was at 25 MPH.

  3.    For the single expansion A's and J's, they were operated at about 25-30% cutoff while running. I have nothing about the cutoff at 70 MPH that you asked for. The A developed a maximum 5350 DBHP at 40 MPH and the J 5150 DBHP at 41 MPH.

  4.    I am adding this from his notes and that is about efficiency of each class. The improved Y5/Y6's, under optimum conditions with a fully loaded trains near its maximum DBHP rating, were about 6.75-7.25 percent efficient. The A was about 6.5-7.0 percent efficient. The J in passenger service was about 5.25-5.75 percent.

  This is about all I can find on your subject. Hope this helps.

  Bud Jeffries
    ----- Original Message ----- 
    From: nw-mailing-list at nwhs.org 
    To: NW Mailing List 
    Sent: Tuesday, December 20, 2005 3:31 PM
    Subject: Re: speed and cutoff


    John,

    I have some information about some of these classes. But I will need a few days to get to that and dig it out. This time of year is a little hectic, so bear with me.

    Best wishes,

    Bud
      ----- Original Message ----- 
      From: nw-mailing-list at nwhs.org 
      To: nw-mailing-list at nwhs.org 
      Sent: Monday, December 19, 2005 1:07 PM
      Subject: speed and cutoff



            Group,

            Another question may be someone will know or maybe not?

            The class A developed max HP at 40mph, right? With a full tonage train at that speed what would be the average % of cutoff on the reverser?

            The Y6b is at 25mph? % of cutoff?

            S1a at 15mph? %?

            The class J running a heavy train at say 70mph. what would the % of cutoff used?

            I am working on determining the pounds per second of steam being exhausted by these engines. I was looking at the use of other types of front end arrangements (Lempor Exhaust) on these engines. These are the last variables I need to know.

            Thanks,
            John Rhodes
            Virginia

            PS. Louis Newton, Bud Jeffries, Ed King, or others, do you know?



           



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