Greetings from upstate New York, in regards to the dispostion of 
snare drum beaters on either Wurlitzer and B.A.B. organs, one must
remember that B.A.B. was not really into building large organs but
rather the conversion of former book organs to the more economical
media of paper rolls.  

And, rather than having to create a new drum beater mechanism that
would have a reiterating action, they opted to take advantage of the
original configuration of the two existing snare drum tracker ports.
As others have concurred, the results are more musically satisfying
than to have a single port controlling what can sound at times like
machine gun bursts.

Another point in fact is that, when B.A.B. took in an organ for
conversion, they would most likely take in the all music books of 
that organ.  They would take the books and select tunes that were 
ideal for transcription to their music roll scales, as is evidenced 
by the wonderful arrangements of their 82- and 87-key rolls (many of
the latter, being transcriptions from 89-key Gavioli books).  Hence 
it was easier to transcribe an already tried-and-true drum line, 
than to have to calculate a new one around only one tracker port for 
a reiterating drum action.

As with Wurlitzer, B.A.B. multiplexed the drum tracks to include 
the operation of alternate instruments such as a pair of castanettes
(played by the snare drum holes), and a triangle (played by the bass
drum hole).  Wurlitzer had either castanettes or woodblock on the 
snare drum hole, and triangle on the bass drum hole.

Which brings me to an oddity, albeit not what we're generally
discussing, the quandry of why Wurlitzer's APP nickelodeon/orchestion
rolls have the bass drum and triangle playing simultaneously from the
same trackerbar hole (there is no cymbal!).  My hypothosis is that 
when the scale for this roll style was being created, the person doing
so was more organ minded than nickelodeon/orchestion minded.  So, this
person thought that the bass drum hole would be shared with the
triangle by means of multiplexing.

I've always wondered if some of the earlier instruments actually 
had a cymbal and triangle being operated in this manner.  Or was this
just an economy move by Wurlitzer?  I have to admit that the sound of
the bass drum and triangle sounding together, is not too displeasing 
to the ear (although, it could be a little distracting when played
during a classical or semi-classical piece).

Just expounding my 'Too Sense' -- and if I am incorrect, just remember
the words of SNL Weekend Update editorialist Emily Littella: "Never
Mind!"

D.F. Rowe
Bronx, New York
(Currently in upstate New York, recuperating from implant surgery.)