(erielack) Interlockings and Terminology

[A Samostie <quahog_@_sprint.ca>]

Dear Group,

OK, this isn't specifically an EL-related question, but since the thread
on interlockings is running concurrently, I hope y'all can help define
some general railroad terminology.

Just what makes an interlocking an interlocking (as opposed to a
junction, a diamond, etc.)?

I know that many "interlockings" were controlled by towers, and the
various switches and signals were thrown by lever-actuated sheave
cables.  But, many interlockings did not have towers.  For example...
Warbasse Jct. (DL&W Sussex Branch crossing NYSW mainline, referred to as
Hyper-Humus by NYSW).  Were there any interchange tracks at Warbasse, or
just a simple diamond crossing?  If just a diamond crossing, why was
this minor crossing called an interlocking?  There WERE sheave cables
that connected the Lackawanna lower quadrant semaphores and the tilt
board (later smashboard) on the NYSW -- is it the presence of cables
that make it an interlocking?

But, in some cases, where a branch joins a main line, it's referred to
as an interlocking, where I thought it would have been called a
junction.  Or, on Erie and DL&W, was the term "junction" only used to
refer to an interchange with another railroad (e.g. B&O Jct., Andover
Jct.)?

Also, in some places, a crossover is referred to as an interlocking. 
Why?
Does there have to be more than one switch to constitute an
interlocking?  (Obviously, a hand-thrown switch to a spur or siding
isn't an interlocking)!

Cheers,
Alan <quahog_@_sprint.ca>

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