The Cremona Style G that recently was mentioned in the MMD is a piano
that originally played the type "A" coin piano roll.  The "A" roll
was an industry standard for coin pianos that played the piano with
the mandolin rail and one other instrument such as pipes or xylophone.

Cremona never made a piano that used the "G" roll as they had the "M"
roll for their orchestrion models J and K.  The pictures of the Cremona
G on the Digest indicate to me that the stack was changed out with a
stack from a larger piano, as it has more valves than the Cremona G
needs to operate.   I have had several Cremona G models over the years
that I always enjoyed.

The basic coin piano "A" roll has the holes to operate a sustain pedal,
soft pedal, rewind, play, coin trip (off), mandolin attachment, and an
extra instrument.  The play and rewind valves in a Cremona piano are
in the valve box that is attached to the roll frame.  There is a valve
to close the rewind pneumatic and a valve to release the pneumatic by
closing another pneumatic that pushes up a little lever that releases
the lever that held the bigger rewind pneumatic in the closed (rewind)
position.

The stack in the Cremona G actually has the valves to operate the
mandolin pneumatic, a valve for soft and one for sustain pedal, as well
as the valve to turn on the pipes.  The pipes have a pneumatic on the
left side of the pipe chest that when it closes allows air to play the
pipes.

I think the coin trip pneumatic valve is a separate valve in the bottom
right of the piano case and in some instances may be one of the valves
in the stack.  The modulator control in the MMD picture was the late
style that has valves in it that are controlled by a knob on the front
of the case.  It softens the overall piano but still allows the soft
pedal to be operated by the roll.

Just some quick notes that may or may not help.

Don Teach - Shreveport Music Co.
Shreveport, Louisiana