• Walschaert vs. Baker on Hudson 5200, etc.

  • Discussion relating to the NYC and subsidiaries, up to 1968. Visit the NYCS Historical Society for more information.
Discussion relating to the NYC and subsidiaries, up to 1968. Visit the NYCS Historical Society for more information.

Moderator: Otto Vondrak

  by rlsteam
Builder’s photos of the NYC’s “pilot” Hudson, J-1a 5200, show it with a Walschaert valve gear. However subsequent classes all had the Baker gear, and 5200 was retrofitted with the same gear. My question is: What led the NYC to change to the Baker gear on all subsequent Hudson orders, and then Mohawks and Niagaras as well (except, of course, S-2a 5500).

The H-10 2-8-2, the L-2 4-8-2 and the A-1 2-8-4 were all introduced with the Baker gear before Hudson 5200 appeared. However, the last big NYC passenger power before the Hudsons, the K-5 and K-6 Pacifics, had Walschaert gear which they retained throughout their careers. So I am wondering whether the NYC had a preference for the Walschaert on passenger power, but the Baker on modern freight power, until the decision to equip the Js and all subsequent steam classes with the Baker gear. What led to that decision?

I understand the advantage of the Baker gear is that all parts pivot, and there is no large “expansion link” as on the Walschaert, which is more subject to wear. However, that never seemed to impress most other railroads in their acquisition of modern steam power, since the Walschaert -- often called Walschaerts -- vastly predominated.

Did the representative of The Pilliod Company “wine and dine” NYC motive power officials and persuade them to adopt the Baker gear on passenger power as well as freight, countering the overtures of whomever was making the Walschaert equipment? Or was there an engineering factor that impressed the NYC? If so, why weren’t the K-5 and K-6 classes retrofitted with the Bake valve gear?

Any thoughts?
  by NYC_Dave
The 1930 classification book indicates J1-b Hudsons 5291-5249 and J1-c Hudsons 5250-5274 had Walschaert valve gear. Photos show MC J-1b's 8200-8209 with Walschaert valve gear but all the photos of MC J1-c's 8210-8214 I have seen, including a builder's photo of 8210 have Baker valve gear.
J1-b&c Hudsons2.jpg
You do not have the required permissions to view the files attached to this post.
  by rlsteam
Thanks for those images. So after about 1929, around two years after delivery of the first J-1s, the decision was made to go with the Baker valve gear, and those built up to that time eventually had the Walschaert gear replaced with the Baker. Can anyone shed light on the reason the Walschaert gear was abandoned on the Hudsons (but retained on the Pacifics), and after 1929 all new NYC steam was delivered with the Baker gear?
  by ExCon90
I've sometimes wondered about the name with and without the s, and according to Wikipedia the inventor's name was Walschaerts but the patent was erroneously issued with the name misspelled Walschaert--which I suppose means you can make a legitimate argument for either one. On the other hand, the same article cites O. S. Nock's Encyclopedia as saying that the family name was originally Walschaert but the s was added in 1830 when Belgium became independent of the Netherlands and the patent was issued with the spelling Walschaert because that was how the name was spelled in 1844 (?)--I can't make sense out of that, but the upshot seems to be that the family preferred it with the s and the patent was issued without. (I have an idea that the ending with the s is more typically Flemish and may not have been permitted under Dutch rule, which may account for the family's wish to make the change.)
  by Allen Hazen
Based on a brief note in a secondary source (I'll track it down and provide it in a followup), I have the impression that Baker gear may have been superior to Walschaert(s) if you want long valve travel. And based on very fuzzy intuitions I would think that longer valve travel would make for more efficient steam distribution, particularly at high speeds where valve events are of very short duration.
  by Pat Fahey
According to the book THOROUGHBREDS written by Alvin Staufer & Edward May on page 70 . Reads as follows the New York Central had long favored Baker Valve Gear on their freight locomotives , and the very precise light Walschaert valve on their passenger locomotives . The introduction of Baker Gear on the Hudsons marked the beginning of complete system wide total adoption of that gear on all power freight and passenger .
The advantage of the Baker valve Gear was excellent wearing characteristices and ease of maintance .
So it was easy to work with , and alot easier to repair , compared to Walschaerts valve gear .
Maybe the reason for keeping Walschaerts valve gear on the Pacific's , they weren't in as hard of service compared to the Hudsons, this is just a guess . Pat.
  by R Paul Carey
Was it possible the conversion to Baker valve gear was related to the introduction of the Locomotive Valve Pilot on these engines?
  by Allen Hazen
The source I mentioned 3 posts back is "Loco Profile #20: the American 4-8-4" (Profile publications, date may have been 1972). On page 177 (this number of "Loco Profiles" runs from p. 169 top. 192), after a discussion of valves and the problems of steam distribution in large, fast, steam locomotives we have the statement I remembered:
"For travels above 8 in. the Baker gear was universal; below that, Walschaerts almost so."
From which I speculatively extrapolated (i.e. GUESSED) that perhaps Baker gear was superior to Walschaerts if you wanted very long valve travel. (A table on that page shows a number of 4-8-4 designs with Walschaerts gear and 7 to 7 3/4 inches valve travel and three with Baker gear, two with 9 inch travel and the NYC Niagara with 8 1/2 inch travel.)

Alfred W. Bruce's "The Steam Locomotive in America; its development in the twentieth century" (W.W. Norton & Co, 1952 (my copy is an undated Bonanza reprint)), page 201, says
"The Baker valve gear was introduced into steam locomotive practice about 1912-1913 and is an outside gear very similar to the Walschaerts gear in all respects, except that it uses a peculiar double-bell crank-shaped rocker instead of a link. (…) The valve travel may be up to 9 in., and the valve events are comparable with those from the Walschaerts gear, though its action is not quite so smooth."
the section on the previous page about Walschaerts gear says "Owing to the angularity of the link in maximum position, the valve travel is usually limited to about 8 in., unless an increasing lever is used." (Also that "Link and link-block wear are its most objectionable features" -- the sentence I have omitted from the middle of the Baker gear description notes its superiority to Walschaerts in precisely that regard.)

In a steam locomotive running at high speed, the steam ports are open for only a small fraction of a second on each piston stroke. My guess would be that a longer valve travel (by allowing a bit more area to be opened) might somewhat alleviate this. I'm not sure how to interpret Bruce's remark about Baker gear's action "not being quite so smooth" as that of Walschaerts. One POSSIBLE interpretation would be that that the deceleration/acceleration of the valve at the ends of its travel is more sudden with Baker gear (so a graph of the valve's position over time would be more "squared off" -- closer to a "square wave" than a sine wave) than with Walschaerts. If anything, I would think this might be DESIRABLE at high speeds, by lengthening the periods of time in which the inlet and exhaust ports are open. (But remember, I am not an expert, and this is GUESSWORK!)
  by jr
The late Harold Crouch once gave me an explanation on the Walschaerts-to-Baker switch. Harold was a Mechanical Engineer who worked for NYC and successors from about 1946 onward.

(This was specifically in reference to Hudsons) - He said that the Hudsons would typically run mile-after-mile, at high speed along the Water Level Route, without needing much (or any) adjustment to the valve gear. This, over time, caused the Walshaerts link to wear a notch in the spot that had been used so much. This would result in relatively difficult (and therefore expensive) machining in order to correct the uneven wear.

With the Baker, the wearing parts generally consisted of pins and bushings, which were much easier to either replace, or machine back into shape.

It's interesting that you point out the switch started in the late 20s. My impression / recollection from our conversation was that the decision had been made during his tenure, which started shortly after World War 2. This may have been just a mistaken impression on my part. But I am certain that the reason that he gave, for the switch, was the wear on the link.