Russo Loco Wrote:
-------------------------------------------------------
> Interesting photos, Bruce -
>
> That must be one of the earliest uses of a
> Wahlshaerts style valve gear - or at least much
> closer to Wahlshaerts than Stephenson.
> And very clever to have such long lifting links in
> order to minimize the effect of curves to 'notch
> her up' when running forward.*
> OTOH, it's hard to imagine how a connection from
> the Johnson Bar to a Stephenson valve gear could
> have been accommodated.
>
> - Gramp
s
>
> * Or 'open her up' a notch or two in reverse.
Calumet and Hecla Mining Co. #3, the only surviving Mason Bogie has Stephenson gear. Although it and its sisters were built to 4'-1" gauge originally, so perhaps there was a bit more space than the 3' gauge engines to accommodate that.
That being said, there's a pretty interesting set of links to get from the Johnson bar to the valve gear itself, with three or four flexible joints to allow for the articulation of the frame.