Re: Can anyone identify this NG Mason Bogie?

Kelly Anderson Wrote:

> I had thought that all Mason Bogies had Walschaert
> valve gear because the center plate / steam pipe
> swivel joint between the drivers didn't leave room
> for Stephenson valve gear between the frames. I
> guess I was wrong, or are the Stephenson equipped
> engines shown actually just Forney's with a rigid
> driving wheel base?


Some Mason Bogies did indeed have Stephenson valve gear, although I don't believe it was as common as the application of Walschaert valve gear. The last survivor Calumet & Hecla Mining Co. #3 "Torch Lake" at Greenfield Village is one of those Stephenson equipped locomotives, as were the other Mason Bogies (and earlier steam locomotives in general) on that railroad. It was originally a 4'-1" gauge locomotive and it's certainly tight when working underneath between the frame rails. The eccentrics are on the #3 axle and the swivel casting is located just above the #2 axle. There are actually two sets of rocker arms that allow the valve gear motion to circumvent the swivel casting. One is in the typical location within the frame adjacent to the link block. That first rocker arm transmits motion through a connecting rod located behind the #2 driver to the second rocker arm set located within an outboard pillow block of sorts between the #1 and #2 drivers, which then transmits the motion to the valve rod. I'm not quite sure how that would work on a locomotive with two drive axles, but they did exist from what I've read.

This 1970s photo is the best I could find easily showing the external portion of the valve gear on Torch Lake (and some rather thin tires).





Edited 1 time(s). Last edit at 09/11/2020 10:09AM by santafe158.