Y4a to Y5 and subsequent retrofit for Y3's

[NW Mailing List]

Ed, thanks for that detail about 2049. I don’t remember reading that the new exhaust was tried on any locomotives prior to the Y5s. I always assumed they appeared there as a production experiment - and if the 2049 experiment was noted in any published books, I completely read over it.  It probably helps that I’ve taken a greater interest in older steam over the past two years.

Part of that interest was spurred by an article in the N&W Magazine (February 1927) that noted that the Y3b’s (Y4’s) had detail differences in the steam supply and exhaust passages (compared to the Y3s) to allow greater freedom of steam movement. I liked this quote: “The engines should, for this reason, be smarter at speed”. 

Old news is new news again - at least to me.

Matt Goodman
Columbus, Ohio, US

> On Feb 14, 2024, at 8:37 AM, NW Mailing List <nw-mailing-list at nwhs.org> wrote:
> 
> Mike - 
> The first step was the improvement of the LP exhaust system.  The 2049 received a new pair of LP cylinders that took the exhaust o ur the top of the assembly merging the two sides in a sort of bridge  pipe assembly that conducted the exhaust through a pipe shaped like a shallow U that conducted the exhaust to the exhaust stand in the smokebox.  The live steam from the receiver no longer  had to share space with the exhaust .  The results were impressive - the 2049 showed a marked increase in drawbar horsepower as well as the speed at which that horsepower was produced.
> This convinced the MP Dept that all future Y engines would have the bridgepipe exhaust system.
> When the 19 remaining Y5s were rebuilt in 1940-41 their bridgepipe front engines were applied to random earlier 2000-series engines that happened to need repairs.
> Tom Dressler counted sightings of 2000s with bridgepipe front engines and  came up with 22 or 23 that were seen with them, meaning that their was some front engine swapping that went on towoards the end.
> - Ed King
> 
> 
> On Wed, Feb 14, 2024 at 7:56 AM NW Mailing List <nw-mailing-list at nwhs.org <mailto:nw-mailing-list at nwhs.org>> 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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