NW-Mailing-List Digest, Vol 98, Issue 49

[NW Mailing List]

Someone can correct me but a Control point may be any point that affects 
the aspect of a signal.

An interlocking tower may be a control point, interlocking is the method 
of logic that allows or dissallows switch/signal setups for a safe 
aspect display, I.E. the levers connected to a series of moveable bars 
that have notches and stops and other devices attached to it to set up 
the logic of the signals and switches.

The other control point is the track itself if occupied by a train. and 
knocks a signal red.

Today a lot of the signal control is moved to central locations using 
computers, and yes you can still call it interlocking, but its done in 
the computer.

Intermediate signals say a passing siding will have signals at the 
turnouts, in between the main/pass if there is sufficient track 
room/train room if 2 or more trains may be expected or by specific 
design, you could have intermediate signals that could act like normal 
block signals or advance.

For a simple turnout the interlocking could done electrically at the 
turnout with relays, the dispatcher simply aligns it and the aspect 
shows accordingly. The dispatcher may still have signal control to 
direct traffic movement as needed.

-Lynn-


On 8/19/2013 12:00 PM, nw-mailing-list-request at nwhs.org wrote:

> Subject:

> Control points, controlled signals and intermediate signals

> From:

> NW Mailing List <nw-mailing-list at nwhs.org>

> Date:

> 8/19/2013 10:37 AM

>

> To:

> NW Mailing List <nw-mailing-list at nwhs.org>

>

>

> After reading back through the recent posts on signals I think I'm 

> beginning to get a feel for the terminology, but would like to verify 

> my assumptions and ask some questions.  It seems like a control point 

> might be a section of track where there is a controlled signal and 

> that a controlled signal might be one whose aspect is determined by a 

> controller when he sets up a route.  How do these terms relate to 

> interlocking.  My impression of interlocking is a section of track 

> where two or more routes are possible and equipment is in place 

> (signals, derails etc.) prevent collisions.  So is there a 

> relationship between the terms "control point" and "interlocking"?  Is 

> the term interlocking still used?  I think it was stated that 

> intermediate signals are those between control points.  Does this 

> designation include anything besides automatic block signals?

> Jim Cochran


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