Hello, for a local historical park I'm touching up a Woodward/Straube
1923 player piano restored in the 1980s (nice work, Mark Haas!).
I'm mystified by what it uses for roll tracking.  Generally it tracks
well, but there does not appear to be anything sensing the roll edges,
or links from the tracking pneumatic to either the supply roll or the
tracker bar.  Does anyone know of a diagram for this mechanism?  Could
parts be missing?

Dan Harrett