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From: ntt@dciem.UUCP (Mark Brader)
Newsgroups: net.railroad
Subject: Re: large fellow  (That's a Garratt)
Message-ID: <726@dciem.UUCP>
Date: Mon, 20-Feb-84 18:04:34 EST
Article-I.D.: dciem.726
Posted: Mon Feb 20 18:04:34 1984
Date-Received: Mon, 20-Feb-84 22:35:40 EST
References: <378@decvax.UUCP>
Organization: NTT Systems Inc., Toronto, Canada
Lines: 22

I didn't see the National Geographic special, but the locomotive Kenn Goutal
is asking about would be a Garratt.  This is a form of articulated steam
locomotive where there are two driving bogies (trucks), each with its own
cylinders, and the boiler is slung between them.  A Garratt can handle
curves (which abound in South Africa, being a hilly, narrow-gauge country)
much better than any other form of steam engine of comparable size,
because it doesn't have a long rigid wheelbase (or a long boiler like a
Mallet [pronounced Mallay], the form of articulation principally used in the
USA); and since there are no wheels under the boiler, there can be a very
deep firebox.  On the other hand you have to have two flexible joint carrying
live steam to the cylinders, whereas Mallets only need one and non-articulated
engines have none.

Garratts were originally intended for use on very small lines; I think the
first one built was an 0-4-0+0-4-0 (i.e. 4 driving wheels on each bogie and
no other wheels).  But they were eventually built as large as 4-8-4+4-8-4.

I have seen it reported by a reliable writer that the two engine units would
synchronize their beats as the engine proceeded, and by another reliable
writer that this is a myth.

Mark Brader