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Subject: 
Re: Train engine transmission
Newsgroups: 
lugnet.trains
Date: 
Wed, 1 Mar 2000 19:07:09 GMT
Viewed: 
1141 times
  
Fredrik Glöckner wrote:

(This article is about the mechanics of train engines, not necessarily
related to the LEGO train line.  I hope to learn what I need to know
if I'm going to build a train engine in LEGO some day, though, so I
hope this is enough to justify posting the article here.)

I can't answer everything here, but will spit out some information...

The rod coupling works very well with steam engines for the reasons you
surmised. The flexing issues due to curves and bumps are almost nil.
This is not the case in temporary logging and mining lines which is why
the various types of geared locomotives (Shay, Heisler, Climax, and
others) were invented, though the Heisler rod couples the two axles in
each truck (bogie).

I'm not as familiar with Diesel etc. locomotives, but I would guess that
only one axle is driven by the motor when rod coupling is used. Modern
locomotives (which are not Diesel for the most part, they are usually
turbines, if you stand next to one as it winds up, and don't realize
that they use turbines, you may start looking for the airplane...) which
are not totally electric are actually still driven with electric motors.
The Diesel or turbine drives a generator which then runs electric motors
which are usually on every axle.

An interesting note about differentials is that they were tried in the
early days of the geared locomotives, but it was discovered that they
completely lost power in curves, making them absolutely useless.

One place where you can really hear the results of the fact that
differentials are not used in trains is on subway lines, especially in
the Park Street station on the Boston MBTA. There is a reversing loop
there which can't be much more than a 100 foot radius curve, and boy do
the trains squeal going around it.

--
Frank Filz

-----------------------------
Work: mailto:ffilz@us.ibm.com (business only please)
Home: mailto:ffilz@mindspring.com



Message has 2 Replies:
  Re: Train engine transmission
 
(...) Yes, there are several examples of Diesel-mechanical shunters (US=switchers) on which the only powered axle has no whells at all but is simple linked to the drive wheels via these rods Modern (...) You also see Diesel-Electric shunters with (...) (25 years ago, 1-Mar-00, to lugnet.trains)
  Re: Train engine transmission
 
(...) I'd _love_ to see that engine...all you are hearing is the Turbocharger for the Diesel engine spooling up...which, is in effect, a turbine, but it is not powering the train :) The last Turbine powered engines were the UP's 8500HP monsters, and (...) (25 years ago, 1-Mar-00, to lugnet.trains)

Message is in Reply To:
  Train engine transmission
 
(This article is about the mechanics of train engines, not necessarily related to the LEGO train line. I hope to learn what I need to know if I'm going to build a train engine in LEGO some day, though, so I hope this is enough to justify posting the (...) (25 years ago, 1-Mar-00, to lugnet.trains)

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