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From: mangoe@umcp-cs.UUCP (Charley Wingate)
Newsgroups: net.railroad
Subject: Re: Trucks
Message-ID: <1997@umcp-cs.UUCP>
Date: Wed, 19-Dec-84 12:57:44 EST
Article-I.D.: umcp-cs.1997
Posted: Wed Dec 19 12:57:44 1984
Date-Received: Thu, 20-Dec-84 05:25:50 EST
References: <6498@brl-tgr.ARPA>
Distribution: na
Organization: U of Maryland, Computer Science Dept., College Park, MD
Lines: 20

Almost all cabooses these days and all locomotives use what I believe are
called "double-hung" trucks.  These can be identified by two features:

  1.  Transversely mounted leaf springs (the end sticks out of the frame)

  2.  Two short connecting rods or a U-shaped bracket surrounding the springs

The way it works is this:  the car weight rests upon the springs, as in a
normal truck.  Instead of resting directly upon the truck frame, however,
they rest upon a bar which runs across the truck. The ends of the bar are
connected to the bottom ends of the connecting rods, while the tops of the
rods are fastened to the frame.  If you look carefully, you will notice that
the connecting rods point inwards at the top.  This allows the sprung weight
of the car to sway in and out slightly, reducing transverse shocks.  The 
inward cant of the connectors provides the centering force.

I'm sure these trucks have another name, but I can't recall it.  I can't ever
recall seeing them on anything except a caboose or a locomotive.

Charley Wingate   umcp-cs!mangoe