I would like to rephrase the question I previously asked:

 "Given a wide variety of player pianos, all in proper regulation,
  would a roll played at (for instance) "Tempo 80" play at roughly
  the same speed on all the pianos?"

Before I continue, I'd like to state that I am not unknowledgeable
about music.  I have been a performing musician for many years;
I've been a church organist as well as having played in many bands,
orchestras, small wind ensembles, dance bands, and many theater
productions (musicals and opera).  I would also like to state that
my pianos are all in excellent playing condition, and I _am_ aware
of the fact that rolls move faster as they move through the roll.
I am also aware that any printed tempo is really only a suggested
starting speed.

That said, I would like to address a couple things that have been
said in previous replies to my original posting.

 "It is possible to perform most pieces of music at widely differing
  tempos and still produce musically acceptable performances."

While this may be the case to the ears of some people, I have to
disagree with the statement in general.  Any given piece may be played
at _slightly_ different tempos, but not a wide range.  When composers
wrote music, they stated the approximate tempo that it _should_ be
played at.  In earlier days, this was done with "Allegro, "Largo",
etc., although later with the "MM=" to indicate the number of beats per
minute.

  "It may seem to you that a tempo of 55 on a particular roll is wrong
  and far to slow in your opinion."

I do not believe this to be a matter of opinion.  Again, composers had
certain ideas in mind when they wrote the music.  A 'standard' tempo
for marches is 120 beats per minute.  I cannot imagine anyone would
find "Stars and Stripes Forever" to be palatable at 80 beats per minute.

Finally, it is very easy to set a "correct tempo" when one knows a
piece of music.  When early piano rolls were made, I would guess that
for many people, their roll of a particular piece might have been their
introduction to that particular piece.  These days we have radio,
television, CD's, etc., and have much more chance to know a wide
variety of music.  I don't think your average person living in a small
town had much chance to even hear a symphony orchestra ever play.

If I did not know the piece I gave the example of (and sample
recordings) and I played it at the marked tempo of 55, I would have had
a totally incorrect impression of what the composer actually intended.
I still run across some old rolls without tempo markings of pieces I am
unfamiliar with and am sometimes at a loss to know what the composer
may have intended me to hear.

So, my real question is not related so much to interpretation of the
music, but rather to the mechanical aspects of the machines:

  Does marked "Tempo 80" result in "Tempo 80" (approx.) in all well
  regulated player pianos, or did some piano manufactures use a wildly
  different tempo marking scheme?

John Miller
Saint Paul, Minnesota, USA
http://www.PianoRollStuff.com/

 [ Based on MMD articles I checked, all manufacturers except Hupfeld
 [ observed the definition that "Tempo 80" means that the surface speed
 [ of the take-up spool is 8.0 feet per minute.  The owner's manual
 [ provided with new player pianos typically told how to check the
 [ speed and, if necessary, how to adjust the roll motor governor.
 [
 [ But I have a few rolls in my collection whose marked Tempo seems
 [ crazy.  Ed Sprankle suggested that the poorly-paid employee who
 [ stamped the inappropriate marking on the leader was venting his
 [ frustration!  -- Robbie