Author Topic: Modeling complex interlocking signal layouts?  (Read 1032 times)

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pdx1955

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Modeling complex interlocking signal layouts?
« on: January 20, 2017, 08:11:02 PM »
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I keep going back and forth on whether to simulate the actual prototype signal layout at a complex interlocking (multiple lines intersecting, double track etc) or a more simplified version based on actual model track layout. In my case following the prototype as much as possible would mean a number of triple-headed target signals, with a number of heads (especially the bottom) always displaying a red aspect because the modeled track layout and its detection schemes wouldn't ever be able to properly support all three heads. This would be mostly facilitating the "scene" and making something appear bigger than it is shown.

Or...should I use a combination of single/double head targets instead to match the layout trackage? I would still follow SP & UP practices (the intersecting railroads in question here), but base the signal/head/aspect arrangement on the modeled junction instead. It would be definitely cheaper as triple targets are quite expensive but that's not the main focus. Do I stick with following the prototype as much as possible or strive for something that looks right on a operations basis? It's what a railroad would do if faced with my junction versus what a railroad did in actuality.  Maybe it's the same but I keep going around in a circle...

Peter

"No one ever died because of a bad question, but bad assumptions can kill"

John

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Re: Modeling complex interlocking signal layouts?
« Reply #1 on: January 20, 2017, 08:18:45 PM »
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I struggled with this question as well .. I finally settled on 1 & 2 head signals .. Only in a couple of places do I use 3 heads, but one or two heads always displays red -- depending on situation ... with the lower signal head being the one used .. so it's easy to just put red LEDs an power them ..








« Last Edit: January 20, 2017, 08:22:08 PM by John »

jagged ben

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Re: Modeling complex interlocking signal layouts?
« Reply #2 on: January 20, 2017, 11:12:47 PM »
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I think one thing that makes a difference is whether you'll be operating the layout by yourself or inviting others to operate it with you.  If the latter, there's an advantage to not having any complicated exceptions to a consistent set of rules.   If it's just yourself, you really can do whatever pleases you most.

John

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Re: Modeling complex interlocking signal layouts?
« Reply #3 on: January 21, 2017, 06:04:44 AM »
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there's an advantage to not having any complicated exceptions to a consistent set of rules.   If it's just yourself, you really can do whatever pleases you most.


Ben is absolutely correct .. its also cheaper from a hardware standpoint not to include the 3rd head .. for example, if you use the SE8C, you can get 4 heads per section -- whereas if you want the 3rd head, then you spill over to another section, and you then need to run more cables. ..  with the 2 head scheme, you can still do speed or route signals that work on the model

another thing to consider is color blind model railroaders who come to visit .. I can tell my guests that the top light is always green, the bottom light is red and so forth .. I use CSX rules, but the only aspects I have is restricted, slow, medium .. I can do limited aspects with two heads, but it adds complexity for the operator ..

http://www.railroadsignals.us/rulebooks/csx14/index.htm

Ed Kapuscinski

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Re: Modeling complex interlocking signal layouts?
« Reply #4 on: January 21, 2017, 09:44:10 AM »
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What is the purpose of your layout?

Which approach best serves that purpose?

C855B

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Re: Modeling complex interlocking signal layouts?
« Reply #5 on: January 21, 2017, 09:55:02 AM »
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... Which approach best serves that purpose?

Typically one of these:

...mike

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

rochsub

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Re: Modeling complex interlocking signal layouts?
« Reply #6 on: January 21, 2017, 10:07:49 AM »
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I went the first route on the UPRR Geneva Sub.  The bottom two lights on both masts are always red on the layout, only the tops signal lights function with the signaling system.  Having visited the prototype many times, I can attest that I very seldom ever saw anything other then red on the lower two lights.

Daryl


randgust

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Re: Modeling complex interlocking signal layouts?
« Reply #7 on: January 21, 2017, 10:14:44 AM »
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I follow the prototype practice based on the actual track configuration on the layout.   I have a prototype rulebook that includes all the proper signal aspects.    My feeling is that anyone that would appreciate 'all the signals' would also be sharp enough to know you're blowing smoke with additional aspects that are there just for decoration.

I never could do that until 3-color single light LED's came out - it's pretty cool to have a proper 'diverging clear' indication on a two-target mast.

ATSF signaling in my area was a complete mish-mash as it changed from LH running Rule 251 on cantilevers over to double-track, bi-directional CTC right at Winslow.   Old stuff and new stuff all mixed up.   Cantilevers, targets, dwarfs, signal bridges.   Most, but not all, target indications were tricolor, with some flashing indications thrown in and other oddball stuff.

One thing I will remind you is that the more complex the interlocking, the more likely it was to be manually controlled.  There may not be a tower there, but a dispatcher someplace may still essentially have an 'east/west/go/stop' on that diamond along with the switch positions.   Track up to it may be automatic block but the actual interlocking - and the related approach - is more often than not NOT part of an automatic block.   Translation?   You may still be manually setting those signals with DPDT's or a computer setting and that's the prototype here.

C855B

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Re: Modeling complex interlocking signal layouts?
« Reply #8 on: January 21, 2017, 11:25:37 AM »
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I follow the prototype practice based on the actual track configuration on the layout. ...manual ...automatic...

This is what I am implementing on my layout, as controlled by JMRI rulebook interpretations, which seem to be moderately thorough. Plan at this point is automatic (semi-ABS + routing) when operating with a small crew or solo, CTC-ish on the mainline when it gets serious (some areas stay ABS), and, like you say, probably semi-manual at a couple of interlockings. So this means three heads at a handful of locations.

If there is a need to economize, one prototype practice I find annoying but used quite frequently in complex interlockings is two-aspect single heads - stop, and a non-specific "restricting". IOW, either "wait" or "enter", with no distinction made for routing.

In terms of operating a layout, it is nice to have routing confirmations from displayed aspects. So I wouldn't display nonsense aspects that don't reflect the routing. But that shouldn't stop you from populating a mast with single-color heads if you were modeling a specific 1:1 scene that has three heads that don't match the layout configuration. Like Daryl and Randy said, leave them red.

Here's something different - I have an interlocking scene with a crossing against non-operating track that would otherwise be very busy on the prototype I'm modeling. What I am contemplating is using a cheap microcontroller like an Arduino to generate a random occupancy on the conflicting track. It would be fed by detection on the operating tracks so it wouldn't be stupid enough to throw a red in the face of an approaching movement, but it would still be there to create operational variety and reflect the (frustrating!) delays normally part of the 1:1. Part of the scene would be functioning signals on the dummy track that would indicate when the microcontroller has cleared a simulated conflicting movement.
...mike

http://www.gibboncozadandwestern.com

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

pdx1955

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Re: Modeling complex interlocking signal layouts?
« Reply #9 on: January 21, 2017, 03:11:39 PM »
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I follow the prototype practice based on the actual track configuration on the layout.   I have a prototype rulebook that includes all the proper signal aspects.    My feeling is that anyone that would appreciate 'all the signals' would also be sharp enough to know you're blowing smoke with additional aspects that are there just for decoration.
...

One thing I will remind you is that the more complex the interlocking, the more likely it was to be manually controlled.  There may not be a tower there, but a dispatcher someplace may still essentially have an 'east/west/go/stop' on that diamond along with the switch positions.   Track up to it may be automatic block but the actual interlocking - and the related approach - is more often than not NOT part of an automatic block.   Translation?   You may still be manually setting those signals with DPDT's or a computer setting and that's the prototype here.

Lots of good thoughts here...
I do have a rulebook so, I plan to match the aspects up as close as possible . This location was tower-controlled so it would be a manual setting to some degree. I think that some heads would be controlled by detection but would be overridden by turnout position. Other heads would be purely turnout position-controlled while some would be a dummy red aspect. I would also have to have a master override to keep the whole plant at stop unless something was being routed through it (as per rules). I have one place on the dummy intersecting UP line to put up a decorative "all red" triple target which matches practice and gives an overall feel to the complexity even though the modeled trackage after it is pretty simple.

Looking at period pictures, I see a local interchange yard lead and a long switching spur coming into the plant with no obvious signals (mast or dwarf) guarding the main tracks, so I can only guess that movements off of these tracks were controlled by radio communications with the tower (going onto probably was indicated by the lower head on the triple targets). [In later years when I visited the site the long spur was still there, but guarded with a triple target which goes with the CTC, remote dispatcher controlled operations versus the 1950's ABS+ tower control interlockings. ]
Peter

"No one ever died because of a bad question, but bad assumptions can kill"

pdx1955

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Re: Modeling complex interlocking signal layouts?
« Reply #10 on: January 21, 2017, 03:36:01 PM »
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In terms of operating a layout, it is nice to have routing confirmations from displayed aspects. So I wouldn't display nonsense aspects that don't reflect the routing. But that shouldn't stop you from populating a mast with single-color heads if you were modeling a specific 1:1 scene that has three heads that don't match the layout configuration. Like Daryl and Randy said, leave them red.

Here's something different - I have an interlocking scene with a crossing against non-operating track that would otherwise be very busy on the prototype I'm modeling. What I am contemplating is using a cheap microcontroller like an Arduino to generate a random occupancy on the conflicting track. It would be fed by detection on the operating tracks so it wouldn't be stupid enough to throw a red in the face of an approaching movement, but it would still be there to create operational variety and reflect the (frustrating!) delays normally part of the 1:1. Part of the scene would be functioning signals on the dummy track that would indicate when the microcontroller has cleared a simulated conflicting movement.

Good enough...single color heads it is! Between Showcase and Sunrise kits , I can assemble pretty much anything I need. There's definite places for main track, diverging, and restricting aspects, so some will need to be manually controlled just for flexibility. I also can't forget that I have a drawbridge in the middle of the plant as well (not modeled as its 'between" a two-sided backdrop), so certain movements could just be set red periodically for realism. Even when the aspects allow movement, its at a restricting 6mph max speed across the bridge.

I also have a spot with a spur line crossing the mainline. Its controlled by locally-set dwarf signals that the other railroad crew activates after contacting the SP dispatcher. At the very least these would be dummy lit aspects set for the main line, but it would be neat to have it able to be set to the intersecting line for interest, maybe using a DPDT switch or a key switch or even remotely controlled with an accessory DCC decoder/JMRI or a 555-timer-based activation circuit.
Peter

"No one ever died because of a bad question, but bad assumptions can kill"

pdx1955

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Re: Modeling complex interlocking signal layouts?
« Reply #11 on: January 21, 2017, 04:17:10 PM »
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What is the purpose of your layout?

Which approach best serves that purpose?

Good straight to the point questions there!

Since the layout is prototype-based as much as possible given the ROW constraints then should I stick as much as possible to the prototype for signalling too. I could operate it by myself, but it is designed to have a small crew, so a semi-automatic/manual approach would probably be best. A lot of the available crew members in this area are prototype operations-focused (with many ex and current railroad employees) so it probably would be good to stay somewhat consistent with expectations.
Peter

"No one ever died because of a bad question, but bad assumptions can kill"

ChrisKLAS

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Re: Modeling complex interlocking signal layouts?
« Reply #12 on: January 24, 2017, 08:12:20 PM »
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With the caveat that I'm fortunate enough to model a prototype (SP) that used route signaling (vs. speed signaling) which vastly reduces the amount of required multi-head signals, I went for option A when that scenario presented itself. If the real signal on the real railroad needed to display a red over red over lunar, I wanted that same aspect on the layout even though my track configuration didn't necessarily require it.

Plus, illuminated multi-head signals look cooler than single-head signals.  :ashat: