Tehachapi signalling thread - prototype

[kc9jts]

Of note is that as of 2007 at least the UP mains at Kern appear to be double track, not CTC.  (I know that west of Sandcut was double-track, not sure if CTC began again anywhere further west.) Same for the BNSF mains. 

It was and is Double Track/ABS between North Bakersfield and Sandcut at least with the first UP timetable governing the area (2001).  We recently changed it to CBS (Controlled Block System, GCOR rule 9.14.2).  An upgrade to Kern Jct itself was just installed about 2 weeks ago; the next phase will make it CTC from North Bakersfield to Sandcut.

[John]

I looked up the rule because I didn't know what a Controlled Block was

9.14.2: Controlled Block System (CBS)On tracks designated in the timetable, movements will run in the direction specified by verbal authority from the traindispatcher or a controlled signal displaying a proceed indication. This authority will establish the current of traffic for the Before granting authority, the train dispatcher must know that conflicting movements are protected.movement.A train must not enter or occupy any track in CBS limits unless:A movement must proceed only in the direction authorized unless authority is granted by Rule 9.15 (Track Permits).A movement authorized in one direction must report to the train dispatcher when it has cleared the main track within CBSlimits. A movement that clears the main track within CBS limits must not reenter that track without new authority unlesswithin Track Permit limits.In CBS limits, Rule 9.15 (Track Permits) is in effect.Rule Updated DateApril 1, 2015System Special InstructionsEffective Date: April 1, 2015

[jagged ben]

I didn't know that CBS was either.  John, you might want to clean up that copy/paste, there's a few bits missing and in the wrong place.  Including:

A train must not enter or occupy any track in CBS limits unless:
A controlled signal indicates proceed.
or
Verbal authority is granted.

So I guess this is a kind of in-between type of control that allows tracks to be used in any direction even if they are signaled for current of traffic?  This is being used as a transition between double-track and CTC? 

[kc9jts]

I didn't know that CBS was either.  John, you might want to clean up that copy/paste, there's a few bits missing and in the wrong place.  Including:

So I guess this is a kind of in-between type of control that allows tracks to be used in any direction even if they are signaled for current of traffic?  This is being used as a transition between double-track and CTC?

I believe it’s signalled bidirectional now.  CBS allows the dispatcher to use either track in either direction without needing track warrants.  The caveat is that once a direction of travel is established it cannot changes unless the block is clear or a track permit requiring restricted speed is issued.

[kc9jts]

While browsing the web I came across a few drawings of Bena-Tehachapi when SP installed CTC.  The drawings show both the old configuration (before CTC) and the new configuration (after CTC).  These are Union Switch & Signal drawings and may be hard to understand if you're not familiar with signal circuits/diagrams.  That being said I figured some of you would enjoy them regardless. 

Rowen to Tehachapi: http://www.rrsignalpix.com/uss_negatives/95_C/USS_C_0162.jpg 
Bena to Rowen: http://www.rrsignalpix.com/uss_negatives/95_C/USS_C_0163.jpg
Index: http://www.rrsignalpix.com/uss_negatives_95_C.php

[jagged ben]

Wow, neat.  Not just for signals but also for other historical details, like spring switches at Bena siding.