Hi Robert and MMDer's, I have limited experience of the Ampico A
lost motion eliminator in that I have rebuilt just one unit.  Strangely
it is in a 1919 5'8" Chickering (presumably retro)fitted with a late
(1927?) A system.

The rail on which the flange fingers rest was missing and I had to
make a new one.  It is raised by three pneumatics, somewhat larger
than a striker pneumatic, located at each break in the string scale.
With about 20" of water lift available these pneumatics are only just
sufficient to raise this rail against the combined weight of the
flanges, lifter rods and the striker pneumatics.

When the soft pedal pneumatic raises the hammers, the back end of the
keys follow.  The lost motion pneumatics are also able to follow but
stop when the capstans on the flange fingers contact the under side if
the keys.  The system does not have enough power to lift all the keys
and therefore stops.  I found nothing which would limit the movement
of the lost motion system and indeed it seems not to be needed.

I have not examined a B system lost motion eliminator but understand
that there are 5(?) pneumatics.  Perhaps there is enough power in this
system to start lifting the keys so that a limit stop is actually
needed.

I hope the above is of some use.  Don't hesitate to contact me if the
above is not clear or more information is needed.

Regards
John Johns
Ottawa, Ontario, Canada