Baker Valve Gear

NW Mailing List nw-mailing-list at nwhs.org
Thu Feb 12 09:34:49 EST 2015 

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
> ------------------------------------------------------------------------
> *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 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 <mailto:nw-mailing-list at nwhs.org>
> *Sent:* Tuesday, February 10, 2015 10:33 PM
> *To:* nw-mailing-list at nwhs.org <mailto: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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