Baker Valve Gear

[NW Mailing List]

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 HuberDeer Creek Locomotive Works
     From: NW Mailing List <nw-mailing-list at nwhs.org>
 To: NW Mailing List <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 tohook 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 4-8-4sit was noted that a half-dozen or so notches either side of center on thereverse quadrant were blanked off so an engineer couldn’t latch the lever thatclose to center. I don’t know that RF&P had that much Baker experience; if I recallcorrectly the only Baker engines they had were the 2-8-4s and the ex-N&WK-3s.  Correct me if I’m wrong; there could have been some early Bakerenginers . . . EdKing 

From: NW Mailing List Sent: Tuesday, February 10, 2015 10:33 PMTo: nw-mailing-list at nwhs.org Subject: Baker Valve Gear Ed -
 I recall hearing from someone a while back that the RF&P and maybeSouthern had problems with the Baker gear as it tended to screw up when set nearcenter. Maybe it was a specific class or application, I don't know, but I heardthat 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 itsattributes 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 sensethat you?re thinking about.  The N&W got dissatisfied with Walschaertsgear early on with the E-1 Pacifics and M-1 4-8-0s, both of which (according toa long-time MP official who was a mentor of mine) that promoted rapid link blockwear.  The M-2s were slightly better, as were the Z-1 2-6-6-2s.  Youare referred to a treatise on valve gear in the ARROW entitled ?MonkeyMotion?.

There was a predecessor of the Baker Valve Gear known as theBaker-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 gearsupposedly gave quicker valve events for any given cutoff but was quitecomplicated.  A simplified version of this gear, known simply as the BakerValve Gear (Abner D. Baker invented the gear, it was marketed by the PilliodCompany 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 PilliodCompany.  Some railroads didn?t think it was worthwhile.  N&Wobviously thought it was worth the cost.

As far as development wasconcerned, the Baker gear offered the advantage of providing a longer valvetravel without introducing excessive angularities into the valve gear. After 1911 N&W never used another valve gear.  The A of 1936 used Bakergear with a long valve travel.  The only refinement thereafter was theapplication of McGill ?Multirol? needle bearings for all the connections in thegear.

When the J came along, I don?t think there was any question ofusing any other valve gear, or using poppet valves.  The Baker valve geardriving 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 thePRR).  Such speeds required driving wheel RPM in excess of 535, almostunheard of elsewhere.  (Charles Faris designed the counterbalancing for theJ; his figures were checked by Voyce C. Glaze whose workbooks are at theN&WHS Archives; the J might have been the most perfectly counterbalancedsteam locomotive ever built, anywhere, anytime).

I hope this ishelpful.

Ed King

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