Here are a couple photos of the player piano auction in Philadelphia,
16 August 2003.  One photo shows the mechanism of the odd early retrofit
player.  [Ref. 030816 MMDigest, Player Piano Auction in Philadelphia
16 Aug 2003]

The rollframe is to the upper right.  This is driven by a pulley inside
the piano on the shaft operating the exhausters attached to the rear of
the piano.  Note the big piece of asbestos in front of motor.

The other photo shows the entry hall at the auction lined with upright
foot-pumpers (and a stove!).  This was only a 20% of the pianos offered.

Phil Jamison

 [ See the photos at http://mmd.foxtail.com/Pictures/  -- Robbie