The strange Cable tracker bar John Tuttle found is for the Solo Carola
expression system.  In 1916 the Cable company introduced three different
expression systems, two different Recordo types and the Solo Carola.
They all used the same note masters.  The Recordo systems were the
early 16 step "A" and the 5 step "B" that we think of today as Recordo.

Solo Carola had a soft rail divided in sections, two notes to a section,
and each section had its own operating pneumatic.  The long slots above
the normal note holes in the tracker bar operated the soft rail sections,
moving them from the soft to the normal position.  Two different width
holes were punched in the rolls.  Notes that played at the base, or
soft, level were narrow and did not open the slots; wide notes opened
the slots and the notes played at a louder level.

The Solo Carola and "A" Recordo systems were made for only a few years.
I know of none that were made after 1919.

Bob Billings