I am presently helping a friend to rebuild the stack in a Ludwig Piano.
The player identification manual from Player Piano Co. lists 2 actions for
this piano, one being a Standard and the other being a Ludwig.  It is
not a Standard so I assume it is the Ludwig.  I can find no information
anywhere on this brand.  Anyone out there ever heard of such an animal?

It is of the double-valve type and all valves are easily removable.
The front cover of the stack comes off without tools.  It is held on
by simple turn pins.  After removing the board all valves are visible.
The tracker bar tubing goes through passages in the stack to the primary
valves which are held on by two screws.  These, of course, are connected
to the secondary  valves directly below them.  Any information would be
helpful.

Eddie Fulmer