Baker Valve Gear
NW Mailing List
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Mon Feb 16 08:26:22 EST 2015
Lois -
I refer you to an article called “Monkey Motion” which appeared in the ARROW a few years back. It contains most of the information to which you refer. Steam locomotives using the Stephenson valve gear which was located between the frames had nothing outside but the side and main rods, with a small rocker arm and a rod to the valve. When the outside valve gears appeared with all the mechanism out there for God and everybody to watch, their actions were described by some imaginative and whimsical observers as “monkey motion”, which became the name of the story. I’m certain that the Society has copies of the issue available if you don’t have one. It covers all the valve gears used by the N&W plus several that weren’t.
EdKing
From: NW Mailing List
Sent: Sunday, February 15, 2015 2:54 PM
To: NW Mailing List
Subject: RE: Baker Valve Gear
A special thank you to all who have contributed information for my article. An eventual article for the Arrow on the same subject would not be out of the question, due to the amount and quality of material I was able to receive. The only real difference would be the focus on the valve gear on modern N&W steam locomotives.
Lois J.Ponton
N&W steam historian
Sent on a Sprint Samsung Galaxy S® III
-------- Original message --------
From: NW Mailing List
Date:02/12/2015 10:49 AM (GMT-05:00)
To: NW Mailing List
Subject: Re: Baker Valve Gear
The majority of steam locomotives around the world did not have power reverse. The screw wheel gives you a significant mechanical advantage over a Johnson bar.
David Jacobs
david.jacobs10 at okstate.edu
405-744-8840 (OSU)
405-372-6031 (home)
405-714-3494 (cell)On 2/11/2015 9:35 AM, NW Mailing List via NW-Mailing-List wrote:
This is a very interesting topic. I had never heard that the Walschaerts would jump into reverse before. Possibly so.
It seems, though, that Walschaerts was a more common VG than Baker throughout this country and the world. I also understood that Baker required a royalty payment and was more complex and heavier with many more parts than WVG. Perhaps that could explain the popularity of the WVG? Personally I prefer the looks of the Baker and I'm glad to see N&W favored that type VG.
I read someplace that the Baker long travel (their term) was a very rugged VG and was more than able to withstand the forces generated by the more modern engines hence it's more frequent use in the declining years of huge super powered engines.
Who really knows? I'm sure Ed King, Louis Newton and Mr. Jeffries are about the best sources of info around though.
Maybe the WVG issue was why a lot of that type gear on many roads was operated with the screw wheel setup? I understand it gave the engineer very precise control of the VG.
Very interesting discussion!
Roger Huber
Deer Creek Locomotive Works
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From: NW Mailing List mailto:nw-mailing-list at nwhs.org
To: NW Mailing List mailto:nw-mailing-list at nwhs.org
Sent: Wednesday, February 11, 2015 7:24 AM
Subject: Re: Baker Valve Gear
Bob -
I’ve heard of this problem on the Southern. Engineers who tended to hook their engines up too close to center complained that it went into reverse, which might have been explained by too much slop in the reverse linkage. Engineers in the south seemed to be noted for this; when the CG got their 4-8-4s it was noted that a half-dozen or so notches either side of center on the reverse quadrant were blanked off so an engineer couldn’t latch the lever that close to center.
I don’t know that RF&P had that much Baker experience; if I recall correctly the only Baker engines they had were the 2-8-4s and the ex-N&W K-3s. Correct me if I’m wrong; there could have been some early Baker enginers . . .
EdKing
From: NW Mailing List
Sent: Tuesday, February 10, 2015 10:33 PM
To: nw-mailing-list at nwhs.org
Subject: Baker Valve Gear
Ed -
I recall hearing from someone a while back that the RF&P and maybe Southern had problems with the Baker gear as it tended to screw up when set near center. Maybe it was a specific class or application, I don't know, but I heard that and it came from a solid source. That said, obviously N&W figured things out nicely and took full advantage of what Baker had to offer in its attributes vs. Walschert or others.
Does any of this ring any sort of bell to your knowledge area?
Thanks.
Bob Cohen
I don't think any development of Baker Valve Gear occurred in the sense that you?re thinking about. The N&W got dissatisfied with Walschaerts gear early on with the E-1 Pacifics and M-1 4-8-0s, both of which (according to a long-time MP official who was a mentor of mine) that promoted rapid link block wear. The M-2s were slightly better, as were the Z-1 2-6-6-2s. You are referred to a treatise on valve gear in the ARROW entitled ?Monkey Motion?.
There was a predecessor of the Baker Valve Gear known as the Baker-Pilliod gear; it was applied as an experiment to class A 4-6-0 #89. It was used on the first E-2 Pacifics of 1910. The Baker-Pilliod gear supposedly gave quicker valve events for any given cutoff but was quite complicated. A simplified version of this gear, known simply as the Baker Valve Gear (Abner D. Baker invented the gear, it was marketed by the Pilliod Company of Ohio) came out about 1911 and N&W adopted it as standard. The Baker Valve Gear was patented and had to be obtained from the Pilliod Company. Some railroads didn?t think it was worthwhile. N&W obviously thought it was worth the cost.
As far as development was concerned, the Baker gear offered the advantage of providing a longer valve travel without introducing excessive angularities into the valve gear. After 1911 N&W never used another valve gear. The A of 1936 used Baker gear with a long valve travel. The only refinement thereafter was the application of McGill ?Multirol? needle bearings for all the connections in the gear.
When the J came along, I don?t think there was any question of using any other valve gear, or using poppet valves. The Baker valve gear driving the J?s big valves helped the engine to attain speeds of over 110 MPH (read Dave Stephenson?s treatises in the ARROW about the 610 tests on the PRR). Such speeds required driving wheel RPM in excess of 535, almost unheard of elsewhere. (Charles Faris designed the counterbalancing for the J; his figures were checked by Voyce C. Glaze whose workbooks are at the N&WHS Archives; the J might have been the most perfectly counterbalanced steam locomotive ever built, anywhere, anytime).
I hope this is helpful.
Ed King
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