The simplest Themodist tracker bar has only three holes in addition
to the regular 88.  These are sustaining pedal, bass theme and treble
theme.

About the time the Duo-Art was introduced, Aeolian came out with
a line of rolls called "Metro-Art", which were the same as the Duo-Art
recordings except for the absence of perforations operating the
accordion dynamics.  These were in dark brown boxes, but some were put
up as late "Pianolist's Library" selections, with fancy leaders and
boxes of different colors to designate the type of music.

These rolls have the "soft pedal" perforations, same as the Duo-Art,
so the Themodist tracker bars to play them have another large hole on
the right side, somewhat closer to the edge of the paper than the
corresponding sustaining pedal hole at the left.  Oddly, even though
the Metro-Art rolls are truly hand-played, they have the wavy Metrostyle
line, ostensibly just to give the pianolist something to do.  Of course,
the tempo changes are only very slight, unlike the extreme variations
found on most of the earlier "arranged" Metrostyle rolls.

Tracker bars of this period are also likely to have another two
additional holes which align with the edge of the paper for automatic
tracking.  As these holes often collected dust to the point of clogging
the pouches and bleeds, rather than adding sieves that would also clog,
tracker ears are usually found added to the spoolbox and tubing
re-routed to the add-on ear assemblies.

When a piano is later electrified, rarely are holes added to the bar
for automatic reroll and/or shutoff; usually one or more end note holes
are borrowed for this purpose.  Except for playing Duo-Art rolls, the
holes would have to be added and nipples glued in, compromising the
bars originality and usually done in an amateurish fashion.

The very first Duo-Arts had only the large hole at the extreme left for
shutoff.  Thus, a pedal/electric Themodist Pianola originally built as
such during the same period would have this hole also (but I've never
seen one).

Jeffrey R. Wood