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From: stimac@tymix.UUCP (Michael Stimac)
Newsgroups: net.railroad
Subject: Pennsy signals are called ...
Message-ID: <626@tymix.UUCP>
Date: Wed, 22-Jan-86 14:39:22 EST
Article-I.D.: tymix.626
Posted: Wed Jan 22 14:39:22 1986
Date-Received: Fri, 24-Jan-86 21:33:01 EST
Organization: Tymnet Inc., Cupertino CA
Lines: 29

Someone asked in passing what the type of signal used by the former
Pennsy is called.

It is called a "position light" signal. This type of signal was
installed about the same time that the original catenary installations
were made. The reason it was chosen was that it was thought to be
less likely to be obscured by the overhead wires and catenary
supports. The original position light signals had four lights
in a row. This was later found to be unnecessary, and the three-light
rows were then employed.

The color of the lens roundels ("lunar white") was chosen for
maximum visibility in the foggy conditions often found in Pennsy
electrified territory.

The position light signals were also felt to have a high degree
of fail-safe protection. No moving mechanical parts, other
than the controlling relays, and if any lamp position goes out,
the signal can still be read.

Position light signals were also employed on the Norfolk and Western
Railroad.

I am interested in RR signalling, and have enjoyed the recent
discussion along that line. Let's hear more about mainline
railroad signalling, in addition to subway signalling.

Michael Stimac
...ucbvax!hplabs!oliveb!tymix!stimac