Hello MMD'ers,  I have a Lauter player piano in the shop with the
double trackers.  The left tracker has a primary and a secondary valve,
and the right has two primary valves.  All tubing was removed prior to
me seeing it for the first time.

What was the reason for the double trackers and, if you have one,
how was it tubed?

Also, there is a lever at the right hand side of the piano roll.  If
thrown down, it would seem to keep the tracker at a fixed point.
Again, why?

Al Pebworth