My installation of electronic systems goes back to 1978, and includes
all of them.  I have installed Pianocorder since the first "school" they
gave for the installation of those units.  I have installed Pianomation
from the very first few systems they sold.  I agree that the keys should
be bushed, but not to prevent overshooting by the solenoids, because it
will not do that. And if the keys are lifting off the center rail you
will end up with pulley keys and regulation of the piano will be way off
when played by the player.  I can hear when this is happening to a piano
being played.

The pianomation never needs a stop rail.  If you do that you will get
thumping.  The way to do this is to slow down the ding, ding, ding test
so that it repeats a note at the bass end slowly and loudly.  Manually
push the key down with a normal playing pressure so that the key touches
the front rail felt.  Watch for the solenoid to push the key up on the
center rail pin and lower the solenoid rail at that end until the key no
longer pushes up.  Do the same at the treble end of the keyboard.  Check
the middle for possible sag of the rail.  You are, in effect setting the
solenoid rail to correct key dip.

Next you adjust the solenoids so that the rubber bumpers just touch the
bottom of the keys.  On most uprights this will require pulling out each
plunger and inserting an upright regulating felt punching with a 1/8"
hole punched in it.  Some will require two punchings for correct
regulation of the adjustment on the bottom of the pianomation
solenoids.  The hole in the felt serves a dual purpose. 1) allows use of
a length of piano wire to push up the core to judge lost motion. 2)
allows air to escape as the core becomes a small piston and trapping air
will slow repetition. This method of regulation to the piano will not
cause a problem regulating the volume because the solenoid is stronger
when the core is closer to its activated position.  The smaller travel
will cause better pianissimos, louder fortissimos, and better
repetition..  A pneumatic is stronger when it is farthest from the
activated position.  So we pneumo-heads have to adjust our thinking when
working with solenoids.

D.L. Bullock   Piano World St. Louis