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Subject: 
Pneumatically driven locomotive ??
Newsgroups: 
lugnet.trains
Date: 
Tue, 24 Apr 2001 12:58:48 GMT
Viewed: 
435 times
  
Just out of curiosity, has anyone ever succeeded in putting together a
pneumatically driven train?  Reading through some of the posts regarding
the new S@H train offerrings, I got to thinking that it could probably
be done - it would make an impressive feat, and would be pretty
realistic, with compressed air being substituted for compressed steam.

I'm envisioning a battery-driven motor or two pumping like mad to
maintain air pressure in some of the blue tanks, hidden within the black
"fuselage" (please forgive me, I'm still picking up on the train
lingo).  Two of the small actuating clinders could be the actual drive
pistons, one on each side.  Then, using a standard linkage, these
pistons could be connected to the drive wheels.

One air tank could use its air to push the cylinder out.  A mechanical
switch that was somehow triggered by the position of the wheels (and
thus the linkage) could then direct air from the other tank, to pull the
cylinder back in.  By alternating the cylinders/tanks, my thought is
that you could actually turn the wheels, just as in a steam locomotive.

Since the switching of the cylinders is *position* determined, this
system would provide more force initially, when the train has to
overcome its inertia.  The longer the wheel takes to turn halfway (and
activate the switch), the more air pressure builds up, exerting more
torque via the linkage.

Granted, you'd still be using electricity to provide the compressed air
- I guess its a small compromise, considering the inadvisability of
actually having open flames or burning coals on your ABS.  But other
than the compressor motor(s), the system could be compeltely
mechanical.  And all of the components could be hidden pretty well, I
imagine.  It sure would be a beautiful sight to see a LEGO train moving
under its own power ...

So, has anybody tried this?  And if not, who's up for the challenge?
I'm interested in giving it a try, but I'm afraid it's a couple months
away on my list of projects ...

-shaun



Message has 1 Reply:
  Re: Pneumatically driven locomotive ??
 
(...) I have always wondered how steam engines do deal with pistons winding up dead center. With a car, the starter motor gets the fly wheel going, so there is already momentum before the pistons start firing, but with a steam locomotive the pistons (...) (23 years ago, 24-Apr-01, to lugnet.trains)

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