The 48-key scale is based on the 46 Gavioli scale, which has no
registers.  The 48 has an additional 'forte' and 'piano' register.
The musical scale is very similar to the 56 Limonaire scale which
is a standard for medium sized street organs, the only change being
that all the basses move up one note, losing one accompaniment note
in the process, and you can then have lots of registers.

Because of these similarities music is readily available for 46-, 48-,
52- and 56-key or keyless scales, the note patterns being identical,
and the noteur will make the simple changes depending on the actual
scale.  There are many noteurs for these scales in Europe, but make
sure you chose one who is a good arranger, rather than one who can
supply immediately!

The musically knowledgeable will detect major differences between the
European music and that arranged for the Wurlitzer 125 and 150 scales.
The latter are badly designed, with their parallel runs of trumpets and
melody.  The 46/48 scale has eight basses and an almost fully chromatic
melody whereas the Wurlitzer 150 scale must be the worst scale ever
designed of that size.  Size for size, European organs are far superior
to the American ones, but then I would say that!

Regards, Nicholas Simons