The comments from James Black in 081107 MMDigest were of interest, 
because my TriumphAuto player has the type of tracking system that 
he described.  He is spot-on as to the logic involved.

The TriumphAuto was made in England, using an action supplied by The
Autopiano Company, New York, N.Y.  One other company, Standard Player
Action Company, also of New York, N.Y., employed the same scheme with
the four tracker holes.  I have copies of two small pamphlets that each
of those companies produced, re-printed by the (now defunct) Vestal
Press of Vestal, New York.

The pamphlet, "Player Piano Pointers" of the Autopiano company, has 
an illustration of the two downward-facing large tracker pneumatics
bracing the valve box and a cutaway view of the valving.  The
illustrations are not very clear and there is no discussion about the
action.  On the illustration page there is a hand-drawn sketch that was
added by someone, showing the tubing connections to the tracker bar.

I can testify that mixing up the tubing causes strange and bad 
behavior.  The booklet, "Principles of Player Action Operation" by
Standard, has fairly good illustrations and a good explanation of the
valving and logic.

I have never had a [narrow] music roll that would require the inner 
holes, but at least the restoration is done correctly -- I had to put 
one new pouch in the valve block.  I am wondering if Aeolian also used 
the Autopiano action or was licensed by them in some way.

Bill McKeown
Euless, Texas