Signal Complexity

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johnpenn74
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Signal Complexity

Post by johnpenn74 » Sat Oct 27, 2018 9:04 pm

Can I elicit some opinions on the acceptable level of complexity of signals on a live steam railroad? I would like to hear any horror stories about making things to complicated or perhaps success stories where in application of "Prototypical" heads achieved the desired result without confounding the regulars and visitors.

As it stand on EPRR we have a single face GAR using manual captured block. As we are double tracking portions of the main, I am working towards changing portions over to autodetected Absolute Permissive Block.

My inclination at this time is to use two Face Route Signal (Not speed signals) and even throw in an occasional Lunar for good measure.

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NP317
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Re: Signal Complexity

Post by NP317 » Sat Oct 27, 2018 10:48 pm

This summer (after the Triennial) I visited Train Mountain, and attended a signal familiarization class with their creator.
Of interest to me was their complexity: more than necessary.

There are THREE different indications that all end up meaning the same specific occupancy situation, with several different Lunar indications involved.
I asked the designer about this, and he admitted he was trying to represent several different prototype signal systems.
I pointed out the obvious: that as a short term visitor, I would have difficulty remembering signal meanings because of this complexity.
(For those familiar with TM's signal system: If I am incorrect in any of this information, PLEASE correct my understanding.)

Bottom line: Signal systems should be simple and consistent so that visitors can safely navigate the railroad.
Especially one as complex as Train Mountain.
~RN

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BigDumbDinosaur
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Re: Signal Complexity

Post by BigDumbDinosaur » Sat Oct 27, 2018 11:12 pm

johnpenn74 wrote:
Sat Oct 27, 2018 9:04 pm
Can I elicit some opinions on the acceptable level of complexity of signals on a live steam railroad?
Defining an "acceptable" level of complexity is somewhat like defining an acceptable level of taxation. It's all a matter of opinion. :D

That said, you have to keep your target "audience" in mind: hobbyists. Most of them are not and never have been railroaders. Hence a truly prototypical ABS may demand more understanding than many hobbyists are willing to bring to bear. My own club is typical in that regard. Only a few of the members who regularly run trains have a (full-sized) railroading background. That especially becomes apparent when members leave turnouts open after dropping cars into stubs, back down the mainline without a flagman, or barrel past a signal displaying stop and foul a track on which another train has the right-of-way.

Anything more complicated than basic, three-aspect signaling is likely to become an operations headache for you. At EPRR, some facing point turnouts will be well-served by double-headed signals that display routing as well as permissible speed—routing information would be very useful at night. However, that's about as complicated as I would make it. In hobby signaling, complexity tends to elicit mistakes that may lead to cornfield meets or caboose-crunching.
I would like to hear any horror stories about making things to complicated or perhaps success stories where in application of "Prototypical" heads achieved the desired result without confounding the regulars and visitors.
While I can't give you any outright horror stories concerning signaling on a 1-1/2" scale railroad, I have witnessed plenty of near-misses at our club due to engineers failing to obey signals—and our ABS is basic three-aspect. Also, we had an infamous incident in which a certain engineer was highballing south on the outside mainline and ignored signal 2102, which was displaying stop. He was the only one on the track at the time, so he decided the ABS had to have malfunctioned. It had not. What had happened is he left a couple of cars behind the last time he was rounding the curve into the tunnel—no safety chains, of course. Those cars were still sitting in the curve in the block, which is why signal 2102 was at stop. It was nighttime and quite dark. The cars would not have been visible until the last second... :D
As it stand on EPRR we have a single face GAR using manual captured block. As we are double tracking portions of the main, I am working towards changing portions over to autodetected Absolute Permissive Block.
Having had the recent experience of running EPRR, I would opine that a full APB is probably overkill for most areas. Your regulars are already accustomed to standing at the passing tracks waiting for an opposing train to clear the next block. I would be inclined to retain that arrangement from an operational standpoint and avoid the complexity of a full APB. Depending on the block, some permissive signals in between headblocks can maintain train intervals. In other words, you'd be automating the slap switch setup but adding some intermediate signals to allow more than one train to occupy the track between meets. The logic to do this will be a lot less difficult to implement than full APB, and easier to troubleshoot should something go on the fritz.
My inclination at this time is to use two Face Route Signal (Not speed signals) and even throw in an occasional Lunar for good measure.
Standard three-aspect signaling (clear, approach, stop) would work well at EPRR. A lunar will confuse those who have not had full-sized railroad experience. As a former signal maintainer, I revel in complexity. However, most people who are in this hobby are interested in running trains, not studying for the Amtrak engineer's exam. :D Don't make it complicated! Pick a basic three-aspect pattern, such as the Santa Fe rules that existed before the formation of the BNSF.
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Erskine Tramway
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Re: Signal Complexity

Post by Erskine Tramway » Sun Oct 28, 2018 10:02 am

BigDumbDinosaur wrote:
Sat Oct 27, 2018 11:12 pm
Standard three-aspect signaling (clear, approach, stop) would work well at EPRR. A lunar will confuse those who have not had full-sized railroad experience. As a former signal maintainer, I revel in complexity. However, most people who are in this hobby are interested in running trains, not studying for the Amtrak engineer's exam. :D Don't make it complicated! Pick a basic three-aspect pattern, such as the Santa Fe rules that existed before the formation of the BNSF.
I agree with BDD. I was on the BN when they installed signals on our Subdivision. Before that, the Alliance Div. 3rd. Sub. was Dark (non-signaled) territory. The mainline signals have four indications, Red (Stop), Yellow (Approach the next signal prepared to stop before passing any part of the signal, trains exceeding 35 MPH must immediatly reduce to that speed), Flashing yellow (proceed prepared to pass the next signal not exceeding 35 MPH), and Green (Proceed). In practice, you can run track speed all day following on Flashing Yellows (Approach Medium), as long as you don't get to a Yellow. Lunars are used to start non-signalled track, as on all the mine leads in the PRB. Lunars are sometimes hard to see in the daylight, so they were being replaced with Flashing Reds.

Since most modelers don't have the experience, or maybe even the interest, in running on signals, the most simple you can use would be best. If you wanted to use the occasional Lunar, it should be a 'low' signal leading into, say, an un-signaled yard. The tricky part in the whole thing is, as BDD has noted, getting people used to actually obeying the indications of the signals, and making them 'intuitive' enough that a visitor isn't overwhelmed.

Just my 2 Cents.

Mike
Former Locomotive Engineer and Designer, Sandley Light Railway Equipment Works, Inc. and Riverside & Great Northern Railway 1962-77
BN RR Locomotive Engineer 1977-2014, Retired

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NP317
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Re: Signal Complexity

Post by NP317 » Sun Oct 28, 2018 11:36 am

Please define the abbreviations used. Not everyone understands their meaning, and it is always helpful.
I know some of them, but not all.
ABS
APB
EPRR
GAR
BDD (Oh wait! I know that one...)

Thanks.
~RN

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BigDumbDinosaur
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Re: Signal Complexity

Post by BigDumbDinosaur » Sun Oct 28, 2018 1:20 pm

NP317 wrote:
Sun Oct 28, 2018 11:36 am
Please define the abbreviations used. Not everyone understands their meaning, and it is always helpful.
I know some of them, but not all.
ABS
APB
EPRR
GAR
BDD (Oh wait! I know that one...)

Thanks.
~RN
ABS: Automatic block signals or automatic block signaling.

APB: Absolute permissive block. APB is a specialized form of bi-directional ABS that is found on single-track mainlines. See here for a good discussion on APB.

EPRR: Eagle Point Railroad.

GAR: Green, amber (yellow), red.

BDD: Big, dumb and dumber. :D
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Re: Signal Complexity

Post by BigDumbDinosaur » Sun Oct 28, 2018 1:29 pm

Erskine Tramway wrote:
Sun Oct 28, 2018 10:02 am
The mainline signals have four indications, Red (Stop), Yellow (Approach the next signal prepared to stop before passing any part of the signal, trains exceeding 35 MPH must immediatly reduce to that speed), Flashing yellow (proceed prepared to pass the next signal not exceeding 35 MPH), and Green (Proceed).
Approach medium (flashing yellow) is replaced on some roads by overlapping approaches, which simply means a given signal stays at approach until the train is two blocks away from the block being governed by the signal, instead of just one block. Either approach (!) is not difficult to model, but doesn't offer much in riding scale. Our trains are not running that fast and are not all that heavy that braking distances are a problem—assuming the train has brakes! :D
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NP317
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Re: Signal Complexity

Post by NP317 » Sun Oct 28, 2018 6:50 pm

Thanks, BDD!
:lol:
~RN

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Re: Signal Complexity

Post by rkcarguy » Mon Oct 29, 2018 11:16 am

Switch point sensing and train detection can be used to easily manipulate a second head on a signal with R/Y aspects. It looks like you plan on R/Y/G though permitting full speed siding operation? I've worked this out with some relays and diodes to get it to function right with R/Y (just played with wires, signals, diodes, and some sections of HO track in the living room as a test).
Basically, turnout thrown indicates a red over yellow aspect unless it is over-ridden by a red(train detected in siding already-Red over Red). If the turnout is not thrown to the siding, the lower target is also red and the upper will depict whatever situation is on the main at that time. I've made some little dwarf signals with R/Y, and when a train is exiting a siding, turnout position and detection from the main line also controls this signal. This gets more complicated if you have bi-directional traffic on the sidings though, unless your crews/system are prompt with returning the mainline turnout to position after the train has entered the siding, preparing to exit the siding, both ends of the siding will show yellow without some sort of direction sensing. Mine is easy enough because I've decided that I do not want to slow down or stop uphill trains, so only downhill traffic will use the siding and it only needs to be signaled on its "exit" end.

Only the "base" relay circuit of this is the hardest to wire, because the turnout indicator switch that sets the lower target yellow, also must have another wire with a diode to trip the upper target red. Yet another relay is used to sense occupation of the siding and cancel the lower masts yellow to red, if occupied.

How is EPRR's current signal system controlled? Relay/Diode Matrix?

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BigDumbDinosaur
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Re: Signal Complexity

Post by BigDumbDinosaur » Mon Oct 29, 2018 3:20 pm

rkcarguy wrote:
Mon Oct 29, 2018 11:16 am
How is EPRR's current signal system controlled? Relay/Diode Matrix?
It's a manual (slap switch) system.
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rkcarguy
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Re: Signal Complexity

Post by rkcarguy » Mon Oct 29, 2018 4:05 pm

Information about how those work seems to be somewhat secretive, but it can't be much different than a relay diode system except with a slap switch instead of sensing the train across the rails.

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Re: Signal Complexity

Post by rkcarguy » Mon Oct 29, 2018 4:17 pm

The flashing yellow really ads a level of protection by giving that extra block of safety between two trains. it didn't help these guys though.
I agree that it's not needed for a model RR operation unless that's the prototypical experience/time period you are really wanting to emulate.

https://www.youtube.com/watch?v=6I5XYIbzZ5Q

Actually it looks like this video was cut. The original had the train approaching a signal with a flashing yellow aspect first, then the yellow, then the red over green goes red/red when the oncoming train fouls the diverging route. Ouch!

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