I have enjoyed the recent comments on mandolin rails.  I have seen a
variety of rail materials on old player pianos, the most common being a
clip-on metal device, followed by a glued-on wood piece.  Also,
material for the individual notes has been comprised of various
materials, with leather being most common, followed by rubberized
cloth.

I would love to see some input concerning best thickness of leather to
use for the individual notes and also sources for clip-on metal tabs or
other metal material which might be on the market.

I am currently working on a Seeburg A that uses a heavy leather and a
glued on piece of soft wood that is so ineffective that when the rail
is applied, it is more of a mute than a pleasant sound.  I want to come
up with something that, when the rail is on, has a brilliant and
beautiful sound.

Larry Schuette, The Player Piano Man