Baker Valve Gear

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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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