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From: hrs@houxb.UUCP (H.SILBIGER)
Newsgroups: net.railroad
Subject: Re: Re: Subways of US and Canada - furth - (nf)
Message-ID: <319@houxb.UUCP>
Date: Wed, 11-Jul-84 08:33:41 EDT
Article-I.D.: houxb.319
Posted: Wed Jul 11 08:33:41 1984
Date-Received: Thu, 12-Jul-84 03:24:39 EDT
References: <963@dciem.UUCP> uiucdcs.20600012
Lines: 24


Depending on the type of suspension used for the overhead (trolley)
wire, a switch to pantographs may be possible. Some overhead wire
systems use a "t" system to hold the wire. In the t system the
support wire is straight, and a t shapped fitting holds the
trolley wire, such that it is below the suspension wire ( at
the bottom of the t.) In the u system, a fitting like
an inverted u is inserted in the suspemsion wire, and
the trolley wire is in the inverted u. In the t system it
is easy to convert to pantographs, since there are no
obstructions at the same level as the wire. With the u
system, wich is used in Toronto, the trolley wire
ends up at the same level as the suspension cable,
and it is not possible to use pantographs without
extensive changes. 
Crossings of streetcar and bus lines, when pantographs
are used are handled by isolating the trolleybus return
wire at the crossing. The bus is then not powered for
that short distance.

By the way, the half pantograph is called a Faively
pantograph.

Herman Silbiger