Author Topic: Tehachapi signalling thread - prototype  (Read 11006 times)

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kc9jts

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Re: Tehachapi signalling thread - prototype
« Reply #75 on: January 07, 2019, 07:50:12 AM »
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Old thread but something new to add...

http://www.railpictures.net/photo/682686/

Proof that there was once a triple-head signal at the west end of Woodford, to indicate if the short siding turnout was thrown.     (And this is Woodford.  Steve has been known to be imprecise on some details.  Compare this view (transformer bank lower right) and this one with the same electrical box on pole in background, which is blurred by engine exhaust in the first photo. )   

By 1989 the bottom head was gone (which is similar time frame to the disappearance of the third head at the east end of Woodford).  This signal mast has changed three times since 1986.  Not sure why the second double-head signal replaced the first one.  (Maybe it got lost in a derailment?)

Pardon my ignorance here but did there used to be a second siding at Woodford?  I know there was a spur track or two but never knew there was a second full-on siding with controlled switches and all.

kc9jts

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Re: Tehachapi signalling thread - prototype
« Reply #76 on: January 07, 2019, 08:16:29 AM »
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Thanks jb, that makes sense.  If anyone has any knowledge that contemporary practice was/is different, please weigh in.  It's straightforward to change the logic.

Approaching Sandcut from the north (left in the diagram): Each signal will only light if it's approach track is occupied.  Approaching from the south (right, coming from Bena/Caliente) if either approach track is down both signals will light.

Caliente will light both of the double-main approach tracks if either one is occupied.  On the single approach it will light only if the single approach track is occupied.

Guessing in the diagram that Caliente stands in for Bena so the description I gave matches Caliente (not Bena).  All of this is for the searchlights prior to the upgrades in the past few years.  Hope this helps.




jagged ben

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Re: Tehachapi signalling thread - prototype
« Reply #77 on: January 07, 2019, 11:56:09 AM »
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Pardon my ignorance here but did there used to be a second siding at Woodford?  I know there was a spur track or two but never knew there was a second full-on siding with controlled switches and all.

Yes, the spur track used to be the 'short siding', with turnouts at both ends.  The north end was just about underneath the hwy 58 overpass, a little north.  I know this entirely from collected photos and notes found online.  I have seen pictures of a two headed mast at the north end, removed in the 80s along with the bulk of the rail leaving just the spur that's there now.  The south end of the spur remained fully signalled until the mid 90s.   I can post links later if you like.

jagged ben

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Re: Tehachapi signalling thread - prototype
« Reply #78 on: January 07, 2019, 11:58:13 AM »
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Approaching Sandcut from the north (left in the diagram): Each signal will only light if it's approach track is occupied.  Approaching from the south (right, coming from Bena/Caliente) if either approach track is down both signals will light.

Caliente will light both of the double-main approach tracks if either one is occupied.  On the single approach it will light only if the single approach track is occupied.

Guessing in the diagram that Caliente stands in for Bena so the description I gave matches Caliente (not Bena).  All of this is for the searchlights prior to the upgrades in the past few years.  Hope this helps.

So the behavior you describe is not entirely consistent.   Does this have something to do with north of Sandcut being double-track vs south of it being CTC?

kc9jts

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Re: Tehachapi signalling thread - prototype
« Reply #79 on: January 07, 2019, 11:59:09 AM »
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Yes, the spur track used to be the 'short siding', with turnouts at both ends.  The north end was just about underneath the hwy 58 overpass, a little north.  I know this entirely from collected photos and notes found online.  I have seen pictures of a two headed mast at the north end, removed in the 80s along with the bulk of the rail leaving just the spur that's there now.  The south end of the spur remained fully signalled until the mid 90s.   I can post links later if you like.

Sure, as now you have me curious.  I am by no means a Tehachapi Historian or Expert, but I know signaling ;-)

kc9jts

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Re: Tehachapi signalling thread - prototype
« Reply #80 on: January 07, 2019, 12:17:36 PM »
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So the behavior you describe is not entirely consistent.   Does this have something to do with north of Sandcut being double-track vs south of it being CTC?

I may have said this previously in this thread but if not one of the many idiosyncrasies I have found about SP signaling practices is that they were consistently inconsistent with how they did things.  It could have to do with the CTC vs. Double-track.   I am kinda speculating/theorizing here but with the current of traffic double-track the signals were spaced differently and as one direction only would normally see them lit I am guessing they did that to save money on bulbs?

GaryHinshaw

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Re: Tehachapi signalling thread - prototype
« Reply #81 on: January 08, 2019, 12:00:40 AM »
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Approaching Sandcut from the north (left in the diagram): Each signal will only light if it's approach track is occupied.  Approaching from the south (right, coming from Bena/Caliente) if either approach track is down both signals will light.

Caliente will light both of the double-main approach tracks if either one is occupied.  On the single approach it will light only if the single approach track is occupied.

Guessing in the diagram that Caliente stands in for Bena so the description I gave matches Caliente (not Bena).  All of this is for the searchlights prior to the upgrades in the past few years.  Hope this helps.

Oy.  So I guess I was right:

(but I'm expecting the answer to be "it depends").  TIA

but thanks for the response @kc9jts.  And you are correct that I have excluded Bena on my layout due to space constraints.

GaryHinshaw

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Re: Tehachapi signalling thread - prototype
« Reply #82 on: September 16, 2019, 08:44:11 PM »
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I have a question about the searchlight-era signal layout at Kern Junction, as captured in this set of proto-photos:

https://www.redoveryellow.com/signals/tehachapi/T075A_West_Kern_Junction_46159.jpg
https://www.redoveryellow.com/signals/tehachapi/T075B_West_Kern_Junction_46158.jpg
https://www.redoveryellow.com/signals/tehachapi/T075D_West_Kern_Junction_46161.jpg
https://www.redoveryellow.com/signals/tehachapi/T075C_West_Kern_Junction_46164.jpg

I have attempted to reproduce this configuration on my layout (functional, but still only in software):



For the sake of discussion, I have numbered the masts.  Here are my specific questions:

1. On mast #1, what aspect would present for each of the 3 possible routes northbound from track #2?

2. Should mast #4 be a two-headed signal?  E.g., how would one signal that the southbound route is lined for the crossover to track #2?

3. Same as question 1 for mast #6, but I don't follow why there are only two heads for this mast.  In theory there are three possible routes, including two diverging routes.  Is (was) the BNSF directional running into and out of Kern?

Thanks in advance.

C855B

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Re: Tehachapi signalling thread - prototype
« Reply #83 on: September 16, 2019, 09:56:37 PM »
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Lordy, Gary, you are really making me work my memory on this one. Last time I spent any time at Kern Jct. was 48 years ago, just after Amtrak hit. Crimeny, I'm old.

1. Easy. Per SP practice at the time, top head normal, middle head diverging to track #1, bottom head to "BNSF arrive", which was the ATSF main.

2. I don't know since I never managed to spend much time on the Santa Fe side; what I can recall is not seeing any ATSF eastbounds approaching the junction. What I do remember, however, is that what you have labeled as "depart" was a yard lead.

3. This is semi-educated conjecture, not witnessed per se... I would expect red over green (or yellow, rather) for "arrive" and red over lunar for "depart" since like I said, it was a yard lead at the time. Not directional running then. That could have easily changed as Bakersfield's status as an origination and light classification yard was reduced.

To give you an idea of how far back this was in terms of signalling and so on, the ATSF crossing next to their station was manually controlled, crossing attendant and all. I regret not chatting him up.
...mike

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We don't make mistakes, we have happy accidents. We just don't tell anybody. -Bob Ross

GaryHinshaw

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Re: Tehachapi signalling thread - prototype
« Reply #84 on: September 16, 2019, 11:57:03 PM »
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Thanks Mike.  That's pretty impressive for 48 years on! :)  A few follow-up questions, if I may:

1. Your answer for mast #1 makes perfect sense.  I just need to figure out how to tell CATS to show those aspects.  Currently it shows red/yellow/red for both UP#1 and BNSF arrive.  Just a matter if digging a bit deeper into the signal templates.

2. Was "BNSF depart" really a yard lead??  I'm surprised they would connect an ATSF lead to the UP/SP main, but maybe I'm missing something.  (Note that the photos I linked to are c.2007 -- I think the line was bi-directional by then, but I could easily be wrong.)

3. Interesting.  But I'm still puzzled about the function of "BNSF depart" c. 2007.

Thanks again.

C855B

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Re: Tehachapi signalling thread - prototype
« Reply #85 on: September 17, 2019, 12:13:14 AM »
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Oh, 2007 is definitely "modern". Anything post-BNSF merger is modern. I do forget exactly when the roundhouse was razed, it was there in '81, but gone before the merger. The reduction of Bakersfield's status was definitely pre-BNSF, so don't let my stroll down memory lane sway you one way or another. But yes, the "yard lead" connected to SP for enough track for departing but waiting-for-SP trains to clear the ladder so the S-whatevers could burble around making up the next trains. The mainline was what you call "arrive", and bidirectional for through trains.
...mike

http://www.gibboncozadandwestern.com

We don't make mistakes, we have happy accidents. We just don't tell anybody. -Bob Ross

GaryHinshaw

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Re: Tehachapi signalling thread - prototype
« Reply #86 on: September 17, 2019, 02:09:32 AM »
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Hmm, that sounds an awful lot like a departure track to me. ;)  In any event, that's what it must be on my layout given the staging arrangement.

I did figure out how to get CATS to set the aspects I want for mast #1.  The key is to set specific speeds through the various turnout legs.  The real fun will come when I have to actually make a 3-headed signal with 12 leads...  All good things in all good time.  :)