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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.analog
Subject: Re: Spoofing traffic signals
Message-ID: <6713@utzoo.UUCP>
Date: Tue, 20-May-86 23:21:21 EDT
Article-I.D.: utzoo.6713
Posted: Tue May 20 23:21:21 1986
Date-Received: Tue, 20-May-86 23:21:21 EDT
References: <840@ihu1h.UUCP>, <37700004@hpcvlo.UUCP>
Organization: U of Toronto Zoology
Lines: 15

> OK, so setting traffic lights aside, can you tell me how to trigger
> a railroad crossing?  A friend of mine claims that he once did it by
> shorting the two rails together near the crossing with a piece of heavy
> wire ...

Sounds plausible.  The way a train makes itself known to railroad switching
systems is that its wheels and axles constitute a short between the two
rails.  Note that triggering railroad crossing lights and gates is not the
full extent of the effect, since it will show up as a phantom train for
signalling and control purposes as well.  I suspect the railroad would
not be amused, especially if another train had to make a panic stop because
the control system suddenly "saw" a "train" in the section ahead of it.
-- 
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