Author Topic: SP Mountain District (Tehachapi Pass) - N scale  (Read 12924 times)

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Cajonpassfan

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #45 on: July 31, 2015, 03:44:08 PM »
0
Wow, my tongue is hanging out and my eyes are abulging  :o
Sure glad you "haven't had much time to work on the layout" or I'd feel totally inadequate :facepalm:
Beautiful work!
Otto K.

Santa Fe Guy

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #46 on: August 01, 2015, 08:58:41 PM »
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Jaw dropping stuff Chris.
Rod.
Santafesd40.blogspot.com

ChrisKLAS

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #47 on: August 19, 2015, 11:05:32 PM »
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Thanks for the nice comments, guys!

I've been busy building the bridge representing the 5th crossing of Tehachapi Creek. I'm happy with the progress.


jagged ben

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #48 on: August 19, 2015, 11:16:33 PM »
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Tell us about how you made the piers.  (Or is that already upthread?)

GaryHinshaw

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #49 on: August 20, 2015, 03:33:21 AM »
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I don't even know what to say about this pike, except wow.  Your progress and results are unbelievable.

@C855B take note on how to make progress with a massive layout. :)

« Last Edit: August 20, 2015, 03:38:54 AM by GaryHinshaw »

C855B

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #50 on: August 20, 2015, 09:12:56 AM »
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Oh, trust me, it's been duly noted. I got a major chuckle over the pic last year with the not-covered-yet insulation bats behind the benchwork. So been there.
...mike

http://www.gibboncozadandwestern.com

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

ChrisKLAS

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #51 on: April 27, 2016, 07:54:49 PM »
+1
Long time no post! So as to try avoid *completely* hijacking Ed's thread on his own amazing Tehachapi layout and perhaps continue the discussion of signaling on Tehachapi (at least before all the cool signals came down), I figured I'd post a few of the signaling updates that I've managed to put in place on my own layout over the past year here.

For @kc9jts, here's a little video of one of the repeater siding signals in action. This one is at Bealville. I know it's not in the "correct" location, per se, but my version of the siding is unfortunately not 13,000+ scale feet long and I don't have the Bealville crossover, so it'll have to do. One of these days I'll get around to putting the number plates on these too. :ashat:


I've also recently been playing around with the implementation of electric time locks which work pretty well, but will look a lot prettier once all the fascia hardware shows up:

https://www.facebook.com/NScaleTehachapiPass/videos/966308530150964/ (can't embed this one as it's a FB video)

Finally, just a little video of my newly weathered tunnel motors (6 down, 50+ to go :scared:) heading up the mountain, accompanied by a little Liszt.


Going forward, the next steps - at least when I'm not messing around with electronics, which I do way too much of - are to stain the fascia and get the backdrops joint compounded, sanded, and painted. Once that's finished, scenery can begin!
« Last Edit: April 27, 2016, 08:37:11 PM by ChrisKLAS »

ChrisKLAS

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #52 on: April 27, 2016, 08:50:06 PM »
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On the subject of prototypical signaling, I do have a question for you @kc9jts if you'll indulge me:

I was always under the impression that, under the approach lighting scheme used by the SP, if a train occupied either the siding or the main between two control points (let's use Walong as an example), that all four signals protecting both ends (2 for the siding, 2 for the main) would be lit. Recently that's been called into question, however, as I've seen two bits of evidence which seem to contradict this:

- A cab ride video from the loaded cans in the early 90s where they went in and out at Walong due to Maintenance in the Way on the main. At the south (east) switch Walong, heading out of the siding, they had a clear on the dwarf and the mast guarding the main was dark.

- A photo of an uphill train stopped at South/East Bealville, presumably waiting on a westbound headed down the mountain where, again, the dwarf governing the stopped train's movement was red but the mast signal on the main was dark.

This seems a little contradictory to me because, in another cab ride video (headed down the mountain this time), the train went through Walong on clears and the signal governing movement off the siding on the signal bridge just before tunnel 9 was clearly red (of course the signal on the main was showing clear).

Could you perhaps shed a little light on this? Am I correct to assume in light of my (very limited) evidence that all four signals at both ends of a siding would light if the main was occupied, but if only the siding was occupied, only the two signals (one protecting each end of the siding) would illuminate? I've seen photos with the siding signals unlit as well and the sidings weren't unbonded, so I have to assume the dwarves weren't constantly lit.

Changing all of this is just a matter of modifying existing JMRI Logix tables, or setting up new ones, and I'd like to get it right - so thanks for any insight you might have!

jagged ben

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #53 on: April 28, 2016, 12:14:17 AM »
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Chris, is there a particular time period your targeting (so to speak :lol:) for your signals?   I've noticed in photos that there were a couple different series of physical changes to signals in the general time period of the 80s, and I have gathered there were also some signalling practice changes.  Have you figured out when these various changes were? 

Also, if you want to take any part of this discussion over to this new thread, feel free.   :D  I definitely want to make sure you notice it.    I'd be really happy to know all about your research.   :lol:

kc9jts

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #54 on: April 28, 2016, 08:21:14 AM »
+2
On the subject of prototypical signaling, I do have a question for you @kc9jts if you'll indulge me:

I was always under the impression that, under the approach lighting scheme used by the SP, if a train occupied either the siding or the main between two control points (let's use Walong as an example), that all four signals protecting both ends (2 for the siding, 2 for the main) would be lit. Recently that's been called into question, however, as I've seen two bits of evidence which seem to contradict this:

- A cab ride video from the loaded cans in the early 90s where they went in and out at Walong due to Maintenance in the Way on the main. At the south (east) switch Walong, heading out of the siding, they had a clear on the dwarf and the mast guarding the main was dark.

- A photo of an uphill train stopped at South/East Bealville, presumably waiting on a westbound headed down the mountain where, again, the dwarf governing the stopped train's movement was red but the mast signal on the main was dark.

This seems a little contradictory to me because, in another cab ride video (headed down the mountain this time), the train went through Walong on clears and the signal governing movement off the siding on the signal bridge just before tunnel 9 was clearly red (of course the signal on the main was showing clear).

Could you perhaps shed a little light on this? Am I correct to assume in light of my (very limited) evidence that all four signals at both ends of a siding would light if the main was occupied, but if only the siding was occupied, only the two signals (one protecting each end of the siding) would illuminate? I've seen photos with the siding signals unlit as well and the sidings weren't unbonded, so I have to assume the dwarves weren't constantly lit.

Changing all of this is just a matter of modifying existing JMRI Logix tables, or setting up new ones, and I'd like to get it right - so thanks for any insight you might have!

First off let me offer a slight disclaimer and that is that most of what I know comes from looking at signal plans and not from "in-cab" experience (I may need to hide and change my name to avoid getting tarred and feathered but I had a hand in the replacement in a lot of the old stuff on Tehachapi).  Second off, I will answer the next question that has not been asked yet: no, I cannot post the plans as even though a lot of the stuff is obsolete they are still considered proprietary.  And now let me add a third disclaimer: The SP liked to mix things up quite a bit with how each location worked and there could be a lot of variation between similar locations that are adjacent to each other; so really each location would need to be addressed individually.

To your specific question about approach lighting now.......

North Walong has both the trailing signals lit off of the same relay (which combines the track relay for both tracks) so they should be lit together.  The facing signals at North Walong are also lit off the same track relay but as has been previously discussed the bottom head would only light for a diverging move and that is because the lighting circuit for the bottom head had a relay that could check if the top head was better than red.

South Walong was a little different.  Both of the facing heads lit off of the same track relay and it does not appear that it had a provision for the bottom head to be dark for a train lined on the main.  The trailing heads did not light in series with each other as each lit off of their individual track relay.

Most of the track circuits were lit based on a "center-fed battery" that would be located roughly in the middle of the siding and feeding the track relays on both ends.  If there was an engine or real short train on one end of the siding it is possible that only that relay would be shunted whereas the same relay at the other end of the siding would still be energized (the track circuits would have resistors to adjust the shunting sensitivity so in the scenario I just described it is possible that all would be lit or just one side, depending on the adjustments).

East/South Bealville (CP SP340) functioned the same as South Walong where the lights on the main and siding each lit based off of track occupancy on only the track they governed movements from.

Hope this helps



C855B

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #55 on: April 28, 2016, 09:15:29 AM »
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... The SP liked to mix things up quite a bit with how each location worked and there could be a lot of variation between similar locations that are adjacent to each other...

No kidding. This was one of the issues behind the head-on collision in El Monte in 1973. Maintainer jumpered around a relay while testing and gave the w/b a high green into a switch set for the siding and into a waiting eastbound. Killed two. Resulted in a big poster in the office, with a picture showing the bypass jumper headlined "Never, ever do this!"
...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: SP Mountain District (Tehachapi Pass) - N scale
« Reply #56 on: April 28, 2016, 12:49:45 PM »
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Fantastic progress Chris!  It's great to see so much Tehachapi love on this board now.  It helps balance out all the SPF's.   :trollface:

svedblen

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #57 on: April 28, 2016, 01:28:54 PM »
0
I've also recently been playing around with the implementation of electric time locks which work pretty well, but will look a lot prettier once all the fascia hardware shows up:

https://www.facebook.com/NScaleTehachapiPass/videos/966308530150964/ (can't embed this one as it's a FB video)

Neat device there Chris! But I have a question. Why was the prototype mandated to use a time lock? Why not rely on train detection and keep the switch locked until there was no longer any train between the approach signal and the switch? The logic apparently allowed the switch to be thrown when the approaching train had not yet reached the approach signal, but instead started the timer when it had. So the logic already "knew" where the train was, so to speak.  To use a timer seems less safe, to me at least. There is propbably something I just fail to see here, but if so please enlighten me  :)
Lennart

ChrisKLAS

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #58 on: April 28, 2016, 01:47:21 PM »
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Neat device there Chris! But I have a question. Why was the prototype mandated to use a time lock? Why not rely on train detection and keep the switch locked until there was no longer any train between the approach signal and the switch? The logic apparently allowed the switch to be thrown when the approaching train had not yet reached the approach signal, but instead started the timer when it had. So the logic already "knew" where the train was, so to speak.  To use a timer seems less safe, to me at least. There is propbably something I just fail to see here, but if so please enlighten me  :)

I guess the quick and easy answer is to point out that, at some point, any train that was going to clear up back in such a spur had to get back in there in the first place (which would have involved occupying the mainline block while trying to unlock the switch), so keeping the switch points locked in the event of a train in the block may not have worked too well in that situation.  :scared:

Longer version (which, as nothing but an armchair railroader, isn't 100% accurate, I'm sure): Some locks, in CTC territory, were aware of whether a route was lined over the switch and would afford a quick release if that wasn't the case. Some didn't have that capability and, of course, that was out of the question in ABS territory. Some locks were fitted with a quick release track circuit that would allow an immediate unlock if a train was detected to be sitting immediately adjacent to the switch. Some weren't. Some locks energized the shunt relay as soon as the door was opened, while others waited until the crew requested time.

There were a variety of ways these things worked and I've just chosen to implement the basic time lock features (most accurately representing an SL-7 lock, which ran time no matter what), mostly in an effort to slow my local crews down. After all, in the N scale world, even in the aftermath of a major calamity, everyone goes home to their families at the end of the day and the damage is normally limited to plastic couplers and handrails.

ChrisKLAS

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Re: SP Mountain District (Tehachapi Pass) - N scale
« Reply #59 on: April 28, 2016, 01:57:59 PM »
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First off let me offer a slight disclaimer and that is that most of what I know comes from looking at signal plans and not from "in-cab" experience (I may need to hide and change my name to avoid getting tarred and feathered but I had a hand in the replacement in a lot of the old stuff on Tehachapi).  Second off, I will answer the next question that has not been asked yet: no, I cannot post the plans as even though a lot of the stuff is obsolete they are still considered proprietary.  And now let me add a third disclaimer: The SP liked to mix things up quite a bit with how each location worked and there could be a lot of variation between similar locations that are adjacent to each other; so really each location would need to be addressed individually.

To your specific question about approach lighting now.......

North Walong has both the trailing signals lit off of the same relay (which combines the track relay for both tracks) so they should be lit together.  The facing signals at North Walong are also lit off the same track relay but as has been previously discussed the bottom head would only light for a diverging move and that is because the lighting circuit for the bottom head had a relay that could check if the top head was better than red.

South Walong was a little different.  Both of the facing heads lit off of the same track relay and it does not appear that it had a provision for the bottom head to be dark for a train lined on the main.  The trailing heads did not light in series with each other as each lit off of their individual track relay.

Most of the track circuits were lit based on a "center-fed battery" that would be located roughly in the middle of the siding and feeding the track relays on both ends.  If there was an engine or real short train on one end of the siding it is possible that only that relay would be shunted whereas the same relay at the other end of the siding would still be energized (the track circuits would have resistors to adjust the shunting sensitivity so in the scenario I just described it is possible that all would be lit or just one side, depending on the adjustments).

East/South Bealville (CP SP340) functioned the same as South Walong where the lights on the main and siding each lit based off of track occupancy on only the track they governed movements from.

Hope this helps

Thanks a million! The info about both ends of Walong and S Bealville certainly seem to confirm what I've observed. Very interesting, too, that there were facing point absolutes that didn't have the required relays to darken the lower head. I wasn't aware of that! I guess it's time to start reprogramming a few Logix here and there!  :facepalm:

If you're feeling bored or generous (or both!) at some point, I'd be interested in knowing the same info for the following control points which are modeled on my layout. No need to delve into a lot of detail, but just basically whether both leaving signals lit off their own track (or both tracks) and, if it's not too much trouble, whether the facing point signal would've had a darkened lower head.

S Marcel
N Marcel

S Woodford
N Cliff
Note: Woodford and Cliff are combined into one siding on my railroad and Rowen is missing completely :ashat:

N Bealville

None of this affects how my operators will run trains at all, of course, but I think it's such a cool part of the hobby to try to get all the idiosyncrasies of a complicated signal system like this right!

Thanks again! You've already been so helpful and informative that I've nearly forgiven you for whatever hand you may have had in completely ruining the character of Tehachapi Pass!  :RUEffinKiddingMe:

« Last Edit: April 28, 2016, 02:00:27 PM by ChrisKLAS »