Subject:
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Re: Train engine transmission
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Newsgroups:
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lugnet.trains
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Date:
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Wed, 1 Mar 2000 20:05:57 GMT
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Viewed:
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914 times
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> My question is this: Why is this kind of transmission used so much,
> even in fairly modern non-steam engines? My guess is that it is used
> because it allows the axles to have some suspension, while waiving the
> need for a transmission system consisting of universal joints, as
> commonly seen in trucks. The rod-transmission system is probably
> fairly efficient, not having any friction problems, as one would get
> in a cogwheel transmission. Is this anywhere near the truth?
Yes, and there is more of a reason to it than that. It only takes getting the
holes the right distance apart once, vs making gears. Another factor is the
physical size of the connecting cardinal shaft required. For a "average" steam
engine, you are looking at upwards of 100 000 ft lbs of torque available
(Say a piston of 21" dia, a actual force on the piston rods of 138,000 lbs)
The problems of transmitting this much force using gears are quite easy to
identify :), we transmitt about 2.5x this on board ship, and the shafts are
around 2' diameter (hollow), and the gears are about 2' across the faces.
> Also, in a non-steam engine with the connecting rod transmission
> system: How many of the axles are actually powered? Only one, with
> the rest powered via the rods?
If it is rod coupled (GE 44 Tonner, BR 08), then there is one motor per set of
axles. (IE, a 08 has one traction motor, not 3).
_some_ other diesels have idler axles (the FL9's do, and the lightweight
switchers built for CN&CP (EMD1's?)) that you would think are powered, but in
fact are not, they are just there to spread the weight of the engine over a
greater area.
James Powell
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Message is in Reply To:
 | | Train engine transmission
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| (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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