The machine described by Roger Waring is a standard Hupfeld player
piano action, their version of a Themodist Pianola.  It just happens
to be in a particularly nice piano!  It is not a reproducing system --
that would be called a Triphonola.  The system where the controls swing
up from underneath the keybed indicates an earlier model; later ones
incorporate the controls in more conventional positions.

Upright players fitted with Hupfeld Solophonola actions are fairly
common in the London area: Reg Riching's rebuilding shop always seems
to have one or two in when he holds his social meetings.  For some
reason, the only Roenisch uprights I have encountered have been gutted
Triphonolas -- very sad.  The grands that I have seen have all been
ordinary 5'6" Bluthners.

The Solophonola is designed specifically for playing Hupfeld Animatic
rolls, which are accented with the standard 'snakebite' system.  It
achieves the same ends as the Themodist system, albeit with rather
different controls.  The expression system seems to have been designed
to work best in accenting mode.  One I have seen incorporated a 'safety
valve' to admit air if the pianolist pedals too hard, ensuring that the
accompaniment level governor is not overwhelmed.  An interesting
system.

The 73-note roll format was an early Hupfeld venture, and they
maintained their catalogue of recordings in both 73-note and 88-note
format for many years.  The 73-note rolls are themed, with the accent
holes in the centre rather than down the margins, which would account
for the tracker bar Roger describes.

Julian Dyer