Tehachapi Loop II

[GaryHinshaw]

I've been doing some more research and thinking over the various approaches for block signalling and detection.  I am starting to think that for a layout with this kind of very basic operating scheme, that a DCC-based detection system with all the accoutrements may simply be overkill in terms of capability, complexity, and yes, cost.

I agree that for the visible portion of the layout, the only reason to have signalling and detection is because it's cool, not because it will help you operate the layout.  Really almost any system will work fine there. 

It's the hidden staging that requires detection of some kind, and in the end, I really think you're just going to want to see the trains.  (I really can't imagine operating my Vortex without being able to see it.)  Are you planning to build the helix first?  If so, can you then put a temporary backdrop in front of it and try operating it before you make any further detection decisions?

Added - you may have stated this already, but what is the height of the track at the tunnel 10 approach?  If it were over ~55 inches, it would be very practical to have a nod-under there so you could get to the helix.  Then you wouldn't need track detection at all.

[ChrisKLAS]

Slight correction: Cliff still had a diverging approach (red over yellow) aspect and not a restricting as the aspect into the siding.

Good to know, thanks. I never climbed the old shoefly up to tunnel 5 to observe that signal so I was going on third party info, which was obviously "misremembered." 

[jagged ben]

I've been doing some more research and thinking over the various approaches for block signalling and detection.  I am starting to think that for a layout with this kind of very basic operating scheme, that a DCC-based detection system with all the accoutrements may simply be overkill in terms of capability, complexity, and yes, cost.  In exploring possible alternatives, one idea that I find growing on me is to build a single control panel that is a simplified version of a classic Union Switch & Signal CTC machine.

...

I dunno Ed, let me play devils advocate here for a second, and please correct me if any of the following assumptions that are wrong...

> You're gonna run your trains with a DCC system, am I right?  No added cost there.
> You're communicating with us on a computer, not to mention you 'work with that stuff all the time'.  So finding some thing to run JMRI on is probably not really an extra cost either? You probably have an older something or other lying around?
> Maybe this is the biggest assumption, but you'll eventually want signals on the visible portion of layout to light up realistically, right?   So, when you get there, you'll need some kind of detection for that, one way or another.   And are you gonna replicate old analog relay logic in a big board of relays under the layout?  Or just buy a handful of $30-$40 boards such as RR-Cirkits Signalman and Watchman?

So, with 9 visible blocks, maybe 14 blocks in staging (if you really need that many), 12 signal heads...

You could detect all this with 2-3 RR-Cirkits Watchman boards which are simultaneously capable of running LED indicators on your CTC inspire control panel to show you block occupancy for the whole layout (visible + most or all of staging).   I believe you need two Signalman boards.  That's less than $200.   Add another I/O board for detecting your turnout control positions (you can dispense with actually using a DCC decoder to control turnouts, if you wish, although), the adapters for Loconet, etc, other stuff I'm not thinking of.... 

It adds up to maybe $350 for a JMRI based signal system which just compliments the realism of your CTC control panel and makes it more usable.  What's that as a percentage of the overall cost your layout is likely to be?       And you can re-program it whenever any of the jokers on this thread come up with something about the prototype signals that is different than what you thought.   

In summary...
A DCC based signal system and a simple CTC inspired control panel shouldn't be considered mutually exclusive ideas.  You wouldn't be the first person to have a CTC board with a digital backbone behind the scenes.  You can build your control panel just for turnout control now, and then add all the necessary stuff for realistic signals to it later, whenever you decide that you have the desire, and the cash, to stop running trains into each other. 
 
Just my opinion.   

[jagged ben]

I don't want to take over Ed's thread,  ...

Well if you're gonna be like that, I'm gonna have to start a new thread.   So much to respond to (from you and kc9jts) and I'm gonna have to verify it all with respect to fixing our club's version of Tehachapi's signals, which we've apparently done incorrectly.     

Maybe tomorrow though, since I ran out of time typing that reply to Ed.  Anyway, stay tuned...

[ednadolski]

That's correct for a train taking any siding on Tehachapi. Red over yellow unless the siding is already occupied; then red over lunar. SP also liked to save bulb life (at the cost of relays) so they only lit the top signal head when they could get away with it. If you're sitting in tunnel 9 looking at a stop signal at the west switch at Walong, that signal will be red/red. However if it's showing a straight approach or clear, it'll be yellow or green over dark.

Chris, thanks much for the detailed info.  I was doing a bit of digging and found this page: http://lundsten.dk/us_signaling/aspects_sp1996/index.html

Sounds like you are referring to 9.1.11 for the Diverging Approach and 9.1.12 for Restricting.  Would you know: since the speed limit on the main is 23 mph (I think), are trains allowed to maintain that speed thru the diverging routes at Walong siding, or are they required to slow? (to what speed?)

Side note:  I understand that one of the problems with the current double-tracking project is that when Walong and Marcel sidings are joined, there will not be a track without a diverging route at one end or the other.

I actually don't have much info on the CTC machine since that was in use well before my era. I did find out recently that the one down in San Diego, which I always thought was the real one too, is actually a replica. That was a little disappointing.

Yes that is a disappointment to hear.  Nonetheless it looks like they did a pretty good job with it.  Here is another example of someone going all-out to build a US&S CTC machine: http://forum.aorailroad.com/t/ctc-machine-build/169/21

Signals and switches:
North Woodford: signals = 46, switch = 45
South Woodford: signals = 52, switch = 51
North Walong: signals = 54, switch = 53
South Walong: signals = 56, switch = 55

Thanks Nick!  I will update my panel.   Just curious, where did you find that out?

Added - you may have stated this already, but what is the height of the track at the tunnel 10 approach?  If it were over ~55 inches, it would be very practical to have a nod-under there so you could get to the helix.  Then you wouldn't need track detection at all.

The track at its highest elevation will be 60" (I originally had it at 64" bit decided that was too high for best viewing).  I do have an access path to get in there, but the helix cannot be viewed from the onstage portion of the layout since it will be behind the scenery and the backdrop.

 

Are you planning to build the helix first?

Oh yes! in fact construction is already well under way. Here are a couple of (very) recent pics:












The track crew is still making their way up the first lap of the helix.   That's about as far as I can go before I reach a commitment point vis a vis the wiring and detection.  Once the roadbed for the second lap goes in, it will be all but impossible to make changes to the track on the first lap.

Ed

[N.B. jb - I just saw your last posts as I was composing this.  Like yourself I'm out of time for tonight, but I will respond tomorrow. Thanks! )

[ChrisKLAS]

Chris, thanks much for the detailed info.  I was doing a bit of digging and found this page: http://lundsten.dk/us_signaling/aspects_sp1996/index.html

Sounds like you are referring to 9.1.11 for the Diverging Approach and 9.1.12 for Restricting.  Would you know: since the speed limit on the main is 23 mph (I think), are trains allowed to maintain that speed thru the diverging routes at Walong siding, or are they required to slow? (to what speed?)

Side note:  I understand that one of the problems with the current double-tracking project is that when Walong and Marcel sidings are joined, there will not be a track without a diverging route at one end or the other.

Yep, those are the correct rules. I'm not 100% sure, but I would bet that all the diverging routes on Tehachapi are/were good for 23mph (except @ Cliff which, as previously mentioned, was a 10mph siding) so the only thing the signals were really telling crews was which route they'd be taking.

RE the double tracking project, I'd say you're right, since Walong and Marcel resided on opposite sides of the main. I'm not really sure that's a problem though. Even if track speed were 50 or 60 mph, there are ways around having a reduced speed limit on the diverging route. Just such a method actually exists on the very line we're modeling, courtesy of the number 28 movable point frog switch at Bena. The "normal" route for westbound traffic is through the diverging path of the switch and track speed through there is 50, so having a specialty switch meant the railroad could keep both routes through the switch good for 50. Sidenote: seeing that thing in action is pretty cool (and loud) as there are (at least) four powered switch machines that all run at the same time when it's being lined!

[ChrisKLAS]

P.S. Can you please quit your day job and come to Vegas to paint my backdrops? Those look outstanding! 

[GaryHinshaw]

Looking good Ed!  Honestly, if the track at tunnel 10 is ~60", I'd just forgo detection in the helix and nod under to get back there when parking trains.  The track at my 5th crossing of Tehachapi Creek is 57" and I have no qualms nodding under it to get into one of my access holes.  I'm guessing you'll want to leave the fascia pretty short in that area to ease access; you could easily leave a clear view to the bottom few laps of the helix.  They'll be far enough behind the scenery to be fairly unobtrusive, and/or they could be veiled by a curtain.  One of these could also be helpful:



For the visible main line, you should at least plan to include current sensors when you run the bus wire.  You can decide later if you want to use them.  In the meantime, 9 sensors will set you back less than $20.

Seeing these photos emphasizes how big your Loop scene will be! 

[kc9jts]

Thanks Nick!  I will update my panel.   Just curious, where did you find that out?

Ed

Let's just say I work with signals for a living and my paycheck bears the name of a railroad that is great, big, and rolling.

Yep, those are the correct rules. I'm not 100% sure, but I would bet that all the diverging routes on Tehachapi are/were good for 23mph (except @ Cliff which, as previously mentioned, was a 10mph siding) so the only thing the signals were really telling crews was which route they'd be taking.

RE the double tracking project, I'd say you're right, since Walong and Marcel resided on opposite sides of the main. I'm not really sure that's a problem though. Even if track speed were 50 or 60 mph, there are ways around having a reduced speed limit on the diverging route. Just such a method actually exists on the very line we're modeling, courtesy of the number 28 movable point frog switch at Bena. The "normal" route for westbound traffic is through the diverging path of the switch and track speed through there is 50, so having a specialty switch meant the railroad could keep both routes through the switch good for 50. Sidenote: seeing that thing in action is pretty cool (and loud) as there are (at least) four powered switch machines that all run at the same time when it's being lined!

From my understanding you are correct that they would be going 23mph regardless of whether they are taking the main or the siding.  From Ilmon all the way up to Tehachapi all the switches are #14 turnouts that are rated for 30mph (even Cliff has #14 turnouts now although the restriction appears to be related to conditions on the actual siding and not the turnout size).  CP SP328 (Bena) is a #30 turnout which is actually good for 60mph but they have it restricted to 50mph as you said.  With the recent upgrades on the line if the turnout is lined reverse a train will get an Approach Clear Fifty aspect (yellow over green) for a diverging move either direction behind a Diverging Clear or Diverging Advance Approach aspect.  A Diverging Approach aspect will only have a flashing yellow aspect for the approach signal.

[ednadolski]

I dunno Ed, let me play devils advocate here for a second

By all means please do!   I have little knowledge in this area, so all comments are very valuable to me!

, and please correct me if any of the following assumptions that are wrong...

> You're gonna run your trains with a DCC system, am I right?  No added cost there.

Right

> You're communicating with us on a computer, not to mention you 'work with that stuff all the time'.  So finding some thing to run JMRI on is probably not really an extra cost either? You probably have an older something or other lying around?

Yes, that's not really a concern for me.   There are always the inevitable upgrade/replacement cycles over time, but since I want to use DecoderPro and maybe WiThrottle I will have to deal with that anyway.

> Maybe this is the biggest assumption, but you'll eventually want signals on the visible portion of layout to light up realistically, right?

Yes, tho I am more 80/20 about it and I'm not too concerned about strictly emulating the prototype under relatively uncommon conditions (which I likely will never encounter anyway).

(Aside:  Often I am not very sure of what the specific prototype practices actually are for a particular situation )

So, when you get there, you'll need some kind of detection for that, one way or another.

I don't think there is any way to avoid it .   My goal is just to figure out how much of it I really need.  Many of these systems are designed to support much more railroad than I can ever realistically expect to have.

And are you gonna replicate old analog relay logic in a big board of relays under the layout?  Or just buy a handful of $30-$40 boards such as RR-Cirkits Signalman and Watchman?

I definitely want to avoid unnecessarily re-inventing anything.   (Always make new mistakes, I say.  )

So, with 9 visible blocks, maybe 14 blocks in staging (if you really need that many), 12 signal heads...

I came up with a total of 35 detection blocks, which includes the 1' "stop blocks" in the staging helix.  But maybe there is a better way to lay those out?

You could detect all this with 2-3 RR-Cirkits Watchman boards which are simultaneously capable of running LED indicators on your CTC inspire control panel to show you block occupancy for the whole layout (visible + most or all of staging).   I believe you need two Signalman boards.  That's less than $200.   Add another I/O board for detecting your turnout control positions (you can dispense with actually using a DCC decoder to control turnouts, if you wish, although), the adapters for Loconet, etc, other stuff I'm not thinking of.... 

This was my quick list/estimate:

DCC HARDWARE LIST: http://www.rr-cirkits.com/description/index.html

35 detection blocks:
 5 WatchMan @ $42.46ea           $212.30
 35 Coils 5x 8-pack @ $13.60ea    $ 68.00

11 RGY Signal Heads: (33 LEDs)
 3 SignalMan-S @ $32.49ea         $ 97.47

8 Tortoise Motors:
 1 Motorman @ $52.65ea            $ 52.65

Computer Interface:
 1 LocoBuffer-USB @ $62.95        $ 62.95
 1 SSB Gateway @ $26.95           $ 26.95

Power Supply:
 1 12VDC PS-S-12-500  $9.80       $  9.80

                            TOTAL $530.12

OTHER:
 - Cables and Wiring?
 - Panel Switches?
 - Signals and LEDs (Century Foundry/Showcase Miniatures)

It adds up to maybe $350 for a JMRI based signal system which just compliments the realism of your CTC control panel and makes it more usable.  What's that as a percentage of the overall cost your layout is likely to be?       And you can re-program it whenever any of the jokers on this thread come up with something about the prototype signals that is different than what you thought.   

I've been pricing out the hardware to build a panel and that is no free lunch either (hardly a surprise there).  A lot depends on how 'authentic'  I would want to make it, but there again is where I get into 80/20 territory (I reserve the 99/1 for a select few of the trains that are actually on the layout ).  Aside from being cost-prohibitive, anything close to an authentic panel would simply be far too large to be practical. 

In summary...
A DCC based signal system and a simple CTC inspired control panel shouldn't be considered mutually exclusive ideas.  You wouldn't be the first person to have a CTC board with a digital backbone behind the scenes.  You can build your control panel just for turnout control now, and then add all the necessary stuff for realistic signals to it later, whenever you decide that you have the desire, and the cash, to stop running trains into each other.

All quite right of course.  I have not ruled out any system just yet.  Once I have enough helix track down to be useful, I am planning to try out a few options with discrete circuits to see how well they work out.   That may never get past the breadboard stage before I decide it is just not worth the effort and start on a system like you describe.   To be perfectly frank, with the research I have done over the last few days, I am not sure that I will even get very far into breadboarding before I reach my limit.   That probably sounds pretty wet-noodle, but I think that investing in a DCC approach will sit a little easier with me if I feel that I have at least done some exploring into other possible options.
 

Just my opinion.   

And again, very valuable to me! Thanks!


Ed

[bdennis]

Ed,
Just looking at the prices of the devices above.
Have you looked at Digitrax devices such as the BDL168 and the SE8C.
I also use / like Dick's products as well.. Just an option.

[ChrisKLAS]

I just re-read this whole thread from the beginning and have determined that this layout is really gonna be something! 

Not to pick nits, Ed, but on your plan on page 4 (which looks like it came from Anyrail), it looks like you have the track inside tunnel 9 completely tangent. The track there, including the entire section inside the tunnel, is actually on a slight left-hand curve from the perspective of an uphill train. The La Mesa club down in San Diego and my pike are the only two layouts I've ever seen that have modeled this correctly, though while I'm sure it was intentional at La Mesa, honesty compels me to admit that I did it strictly so the track at the bottom of tunnel 9 would come out at an angle that would allow me to cram in a semi-prototypical S-curve between there and Woodford, and I only found out the good news that it was actually prototypical months later after track was already laid.

[jagged ben]

Not to pick nits, Ed, but on your plan on page 4 (which looks like it came from Anyrail), it looks like you have the track inside tunnel 9 completely tangent. The track there, including the entire section inside the tunnel, is actually on a slight left-hand curve from the perspective of an uphill train. The La Mesa club down in San Diego and my pike are the only two layouts I've ever seen that have modeled this correctly, though while I'm sure it was intentional at La Mesa, honesty compels me to admit that I did it strictly so the track at the bottom of tunnel 9 would come out at an angle that would allow me to cram in a semi-prototypical S-curve between there and Woodford, and I only found out the good news that it was actually prototypical months later after track was already laid.

As seen here:
http://redoveryellow.com/signals/tehachapi/033B_West_Walong_29311.jpg

[jagged ben]

...
I came up with a total of 35 detection blocks, which includes the 1' "stop blocks" in the staging helix.  But maybe there is a better way to lay those out?

For the life of me I can only see 31 in your ASCII art diagram.   That saves you a board.  There may be a couple turnout blocks you don't really need either, but I don't think it you can save another board. 

This was my quick list/estimate:
[snip]

Fair enough.  I'm not going to put any more dollar signs in my posts, because just imagine if every build thread on TRW became a discussion of cost.     I'll just make a few additional comments.

11 RGY Signal Heads: (33 LEDs)
 3 SignalMan-S @ $32.49ea         $ 97.47

Here you do have a choice of using two or three color LEDs, and possibly needing 2 instead of 3 boards.     Also per prototype discussions you may not need to drive all three colors on every signal.   With that said, three color LEDS probably look better.  (Trick for 2-color LEDs: use a stronger resistor on the green, so that red is brighter than green, and your blended yellow will be a better amber color.) 

8 Tortoise Motors:
 1 Motorman @ $52.65ea            $ 52.65

Unless you value being able to throw the turnouts from a throttle or computer, rather than from the control panel, DCC control of tortoises isn't necessary or especially worthwhile in my opinion.   If you'll only ever dispatch from the CTC board, you don't need this.  But if you want to throw the turnouts at the top of staging when you've ducked into the middle of the helix, you may like having this.   

OTHER:
 - Cables and Wiring?
 - Panel Switches?
 - Signals and LEDs (Century Foundry/Showcase Miniatures)

Use Cat-5 for wiring.  Not a big additional expense.
As for signals themselves, yes, they are going to cost half or more of the rest of signalling expenses.  Signals are expensive, it's true, there's no way around that.

Here's my final advice on the matter (famous last words).   Buy some or all of the detector coils now, figure out how you will install them in your block wiring, and wiring the busses and blocks with a plan for detection like you said.    It's the cheapest component, and you'll be glad later if/when you decide to implement detection and signalling.   

[jagged ben]

Ed,
Just looking at the prices of the devices above.
Have you looked at Digitrax devices such as the BDL168 and the SE8C.
I also use / like Dick's products as well.. Just an option.

Quick take: 
- SE8C seems to have more capabilities for the price than Signalman, although I can't comment on ease of use.
- BDL168 is quite a bad deal compared to Watchman, not just on price per detector but also because it has to be wired into the actual DCC power feed and draws power from the booster.