Y4a to Y5 and subsequent retrofit for Y3's

Sun Feb 18 14:59:03 EST 2024

Up until this time the N&W locos were equipped with "dome" throttles. Meaning, the mechanism that controlled the supply of steam to the cylinders was mounted in the steam dome". This type of throttle had a number of disadvantages.When starting the loco, steam had to first fill the dry pipe, the superheated header and steam pipes leading to the steam chests. This created a delay in getting enough pressure in order to start the train. When closing the valve to stop, the pressure must subside from the dome forward, again amounting in a delay. So, control of the loco was less than ideal.A dome throttle's position in the boiler prohibits repairs and requires additional holes and required packing in the boiler.By going to the front end Bradford and later the American Multiple Throttle Valve these disadvantages were overcome.Jimmy LisleSent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: NW Mailing List <nw-mailing-list at nwhs.org> Date: 2/16/24  8:50 PM  (GMT-05:00) To: NW Mailing List <nw-mailing-list at nwhs.org> Subject: Re: Y4a to Y5 and subsequent retrofit for Y3's Thank you Ed! It helps to understand how it occurred.  The fact that they were all rebuilt after the Y6's puts it into better context, and moving the first group after the second group to put them into the 2100 series makes sense too. I still question this piece of continuity just a little bit; why didn't the Y6's numbers start after the Y5's at 2110? That does make sense if they already had plans to eventually renumber 2090-2099.One further Y5 question: why did the 2 groups of Y5's have different throttle mechanisms? Can anyone explain the difference in the two mechanisms? Was Roanoke experimenting with a fancy new design?  someone at the forum quoted & linked below states it was on locos 2100-2109 plus 2093. That's the first I've seen it mentioned that one of the original Y5's (Y4a) had it. I can only assume that "Big Jim from Roanoke" is (or possibly was) someone from this group.  Posted by BigJim on Sunday, April 20, 2014 1:37 PMKing/Dressler only mention that some Y5's were thus equipped.The only thing in Jeffries book is that individual Y5's had what was thought to be experimental equipment. Only 2093 & 2100 - 2109 having the Bradford throttle. Not looking into this too deeply, I would suspect that those eleven engines got the American multiple valve throttles when they were rebuilt to the "Improved" specifications.https://cs.trains.com/ctr/f/3/t/229151.aspxMike RectorOn Fri, Feb 16, 2024 at 2:28 PM NW Mailing List <nw-mailing-list at nwhs.org> wrote:Hee is m;y understanding of the   Y-4a Y5s ituation.The railroad built 20 Y engines in 1930, 31 and 32.These engines were not needed to handle the business of the railroad because of the Great Depression.  The first six engines were built with 280 pounds of boiler pressure and were classed Y4a,  After they were on the road it was decided to steam the boilers at an even 300 pounds for which the boilers  had been designed.  These first six engines were reclassed Y5 and subsequent engines were built as Y5I don't know of any information that these engines were built with anything but bar frames.  All were built with plain bearings.  The 2092was destroyed in 1937 inN&W's worst freight wreck up to that time.After the last Y6 engines were built it was decided to upgrade the Y5s and equip them with cast frames and roller bearings, a rather expensive upgrading but it gave the railroad 19 more locomotives of Y6 quality.  They were renumbered 2101 to 2119 but they were not rebuilt consecutely nor was the rennbering done consecutively .So after all this was done and the Y6bs came along the railroad had 100 locomotives that were superbly matched to the needs of the railroad.N&W's 2101-2200 were, hands down, the greatest ,mountain service steam locomotive ever built  and it accomplished its feats with a boiler the size of that of a big 4-8-4.  Compounding made that possible and N*W's continuous efforts to speed the compound up bore fruit.  A Y6 bringing 10300 ton coal trains up New River at speeds between 30 and 32 MPH required the application of about 5500 draawbar horsepower  and any other locomotive that could accomplish that output was a humongous simple articulated with an appetite to match.                         I ask anyone with data that contrdicts any of the above to let me in on it -  I'm more interested in accuracy than anything else- Ed King On Fri, Feb 16, 2024 at 1:13 PM NW Mailing List <nw-mailing-list at nwhs.org> wrote:Ed, thank you for your response to my question. For some reason, I did not get the email through the mailing list, and only received it when Matt Goodman mentioned it and then forwarded it.There is a question I have remaining after your response.  You indirectly addressed it and sort of touched on the crux of the questions with your answer. I thought that the Y5's came in 2 batches.  You mention there were 20 exhaust bridges swapped to Y3's but that doesn't explain why only the first group was rebuilt and renumbered.2090-2099 - 1st group delivered  as Y4a with assembled frames2100-2109 - 2nd group was built with the cast frames and delivered as Y5 (am I incorrect here?)*2090-2099 were rebuilt as 2110-2119 and re-classed as Y5, minus 2092 wreckedMike RectorOn Tue, Feb 13, 2024 at 8:30 PM Mike <mrector333 at gmail.com> wrote:Are there any articles in N&W magazines or annual reports about the retrofit of the first Y4a/Y5 batch from bolt-assembled frames to solid cast frames?  What was the extent of this conversion; did the converted Y5's receive a whole new front engine with drivers/rods/valve gear/etc.., or did they only receive new frames with all the parts getting re-used?  Finally, did the Y3's get immediately converted, as a Y5 was outshopped? I can't imagine leaving those big frames (or whole front engine) lying around the shop for very long.Mike Rector

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