Time Baxter asked in MMD980428:

> What is the fastest number of repetitions a single note should be
> capable of on a well-regulated, properly functioning player piano?
> Stated another way, how fast should a single note be able to repeat?
> Three notes per second?  More?

Far more. The limit must have been reached when Rex Lawson had the
four movements of Rachmaninov's Suite No 2 for two pianos Op 17 cut
from floppy disk by QRS in 1989. The last movement is a very fast
Tarantelle with two sections where one of the pianists is asked to
repeat one note at 12-13 strikes per second. (Usually this is done by
using two fingers alternately.) Rex made these with one punch every
six advances (1/8 inch at tempo 80) to give the action the best
possible chance to repeat. Even so, some players, uprights usually,
won't do it without having the half-blow rail up.

Dan Wilson, London