Hi Jim and MMD,  I have a book by Craig Brougher called
"The Orchestrion Builder's Manual and Pneumatics Handbook" and
it has an entire chapter on building mandolin rails.  There are
some good drawings of various methods.

The book is copyrighted in 1972 and the company name printed in
the book is

  Automata Press
  3500 Claremont Ave.
  Independence, MO 64052
  tel.: 1-816-254-1693

Tim L'Amoureux
timlamour@aol.com.geentroep [delete ".geentroep" to reply]

 [ MMDigest articles about mandolin attachments are indexed
 [ at http://www.mmdigest.com/Archives/KWIC/M/mandolin.html 
 [ Photos of Seeburg, Cremona and Coinola mandolin attachments
 [ are at http://www.mmdigest.com/Gallery/Tech/mandolin.html 
 [ -- Robbie