Signal Complexity

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rkcarguy
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Re: Signal Complexity

Post by rkcarguy » Wed Oct 31, 2018 10:47 am

My simple relay and diode system defaults to green, yellow indicates the 2nd block ahead is occupied, and red = next block occupied.
The system, or block, isn't going to know if it's one train or 4 or a piece of rolling stock that came un-coupled from someone's train. Something is making the connection across the rails and that is that.

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ChuckHackett-844
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Re: Signal Complexity

Post by ChuckHackett-844 » Wed Oct 31, 2018 12:05 pm

Berkman wrote:
Wed Oct 31, 2018 8:47 am
How does a automatic signal system handle multiple train sections within a block?
It depends on the system and what the system uses for the term "block".

In my system, a "block" is one or more (usually)bi-directional, detected track sections between "head-end" signals. The "head-end" signals control entry into the block as well as controlling the reversal of the current traffic flow (i.e.: east -> west, or west -> east). In my system, the head-end signals also ensure that only one train is given permission into the block at a given time (only one entry is cleared to Green/Yellow at any given time) which is not possible with most relay systems that are based on full-size ABS/APB practice.

Some systems use the term "block" to refer to any detected track between any two signals (head-end signals or intermediate signals).

In full-size APB practice there will always be at least one set of intermediate signals between head-end signals to catch the situation where two trains passed a head-end signal at the same time - in which case they will end up facing each other head-to-head at the (Red) intermediate signals and one of them will have to back up to clear the track.

Trains within a block are usually separated by intermediate signals, one between each set of signals. The intermediate signals enforce train separation within a head-end-signal-to-head-end-signal block.
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
Owner MiniRail Solutions (http://www.MiniRailSolutions.com)
"By the work, One knows the workman"

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johnpenn74
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Re: Signal Complexity

Post by johnpenn74 » Tue Dec 11, 2018 11:35 am

Thanks for all the input guys. Here's what I have so far.
1) Signals are route signals not speed signals (cause I like Southern Railroad) Single faces on single track, double stacked faces at switches to indicate divergent/convergent path status (switch position + block occupancy).
2) Nothing is flashing
3) There are no dark faces. If there is a dark face call the maintainer cause something is broken. Avoids the "is it broken or supposed to be this way?"
4) There are no permissive reds based on plaques or signage or anything else on the mast. The light combination is the only indication of what is going on.
5) There are no combined colors. All double faces evaluate to either something over red or red over something (indicating a diverging route / open switch)

I put together the much reduced signal rules for the railroad. Now that I have a plan and a working prototype, we'll see what sticks.

JP
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Re: Signal Complexity

Post by rkcarguy » Tue Dec 11, 2018 11:50 am

I hadn't seen blue before, but you explained it in your other post. Before that I was wondering if there was a sale at Kmart and one takes the diverging route to get there. :lol:
It looks good, and I think the relay matrix is robust and reliable although not "smart" unless you have relays on top of relays on top of relays.
I need to invest in some junction blocks myself, I have been twisting various wires together to get my relay system to perform right and it would be great to be able to just screw on some jumper wires/jumper wires with diodes to make it work how I want it to.
Our local BN, now BNSF trackage had signals that were dark until a train entered the area, I remember the opposing signal I could see would go from dark to yellow, then red, then here came the train. When I was in Oregon on a rafting trip on the Deschutes, the line that follows the river would show green all the time. I prefer that type of system as well, so it's known that it's working.

Berkman
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Re: Signal Complexity

Post by Berkman » Tue Dec 11, 2018 11:51 am

Thanks for the EPRR info. Curious how you handle multiple sections in a "block"? ie how many times one car wonder trains will group up in 2-3 sections and run with the first claiming a signal and the last releasing.

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shayloco
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Re: Signal Complexity

Post by shayloco » Tue Dec 11, 2018 12:50 pm

A comment about multi-color signals: 1 in 12 males (8%) are color blind. That includes me. So if you are concerned about people not following your color coded signal system be aware that 1 in 12 of us may have no clue when presented with these signals.

I prefer signals that are position dependent like semaphores or the system at Mill Creek Central which is color coded but also positional in that the three aspects are a vertical, horizontal or diagonal row of lights.

I applaud your effort at prototypical signal systems but the failure rate of engineers understanding your system starts off at 1 in 12 operators (which is a lot).

I assume that professional railroad engineers must be checked for color blindness. I sure hope so!

-Larry

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johnpenn74
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Re: Signal Complexity

Post by johnpenn74 » Wed Dec 12, 2018 9:37 am

Berkman,
Sectioning is not allowed with in the same block on the prototype, and should not be done on our models. The only protection from a rear end collision is visual. The only reason re get away with it is because out trains are short and loads are small so we can stop faster.

If you really want to get into prototypical specifics, sectioning is based on scheduling. It doesn't mean that you run multiple trains within the same safety signal block.

With capture the flag systems we do it all the time. First guy in takes the block, last guy out releases the block, and the first train out gives a hand signal of "2" to indicate to anyone taking waiting that there is a 2nd or 3rd section train coming.

On an APB/ABS system you put one train in the block and the 2nd train gets held up by the red indication in the previous block. That's the whole reason you have Home and Approach indications, so when you get a yellow you know you are about to hit the red and need to back off. This effectively spreads out the trains by block with a long segment of blocks/track; Just like the prototype. Granted I can't stop operators from running two trains in the same block. I'll offer the argument that 1) sectioning in the same signal block is unsafe and 2) it destroys the illusion we are working so hard to recreate. If operators will use the signal blocks as designed (based on prototype practice mind you) it will regulate the trains the same way the prototype would; bringing us a little closer to the real thing.
John Pennington

Logging meets that actually move logs

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2 Mich-Cal Shays
Allen 4-4-0 Narrow Gauge Conversion
Two Reading A5a Camelback 0-4-0
USRA 0-6-0
Clishay
4 Western Wheeled Scraper NG Dump Cars
N&W 4-8-2
ICM 2-10-2
4 Modern Stake Cars
L&N Caboose
4 Big Four Conversion Gondolas

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johnpenn74
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Re: Signal Complexity

Post by johnpenn74 » Wed Dec 12, 2018 10:01 am

Larry,

I appreciate you catching this oversight. I had no idea colorblindness was as high as 1 in 12!
Per the prototype I will ask HR to start mandatory vision testing so we can start screening and removing operators..... :-P

Er,... no....

I completely understand where you are coming from. BnO CPL and Pennsy PL signals do a much better job of remedying color blindness issues due to the physical position lights are in.

Andy wants from Pennsy lights at Morrison Junct so on the way, but that's a way off.

For now I will off the following remedies:
All faces are three light faces (versus 2 light) and RED is ALWAYS at the bottom. So an operator can determine the POSITION (bottom lit, top lit, etc) of the lights even if you can't discern the color. This will allow the operator to verify RED over RED absolute stop; or Red over something else which is some rule of diverging route. Those those two being most critical to avoiding a collision/emergency stop situation.

Yes I realize this doesn't help at all at night. On another note I am also working on an operating semaphore. Yes I know, doesn't help at night either unless you have a really bright headlight and can see the blade....

I will diligently work on these problems and expect to see you at the next meet. :-)

JP
John Pennington

Logging meets that actually move logs

Project
2 Mich-Cal Shays
Allen 4-4-0 Narrow Gauge Conversion
Two Reading A5a Camelback 0-4-0
USRA 0-6-0
Clishay
4 Western Wheeled Scraper NG Dump Cars
N&W 4-8-2
ICM 2-10-2
4 Modern Stake Cars
L&N Caboose
4 Big Four Conversion Gondolas

Like I'm actually gonna build all this stuff :-P

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BigDumbDinosaur
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Re: Signal Complexity

Post by BigDumbDinosaur » Wed Dec 12, 2018 11:57 am

shayloco wrote:
Tue Dec 11, 2018 12:50 pm
A comment about multi-color signals: 1 in 12 males (8%) are color blind. That includes me. So if you are concerned about people not following your color coded signal system be aware that 1 in 12 of us may have no clue when presented with these signals.
Just what do those 1-in-12 colorblind males do when driving their automobiles and encountering a traffic signal? Do they also have no clue and smash into drivers who are passing through the intersection on a green light? :D
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BigDumbDinosaur
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Re: Signal Complexity

Post by BigDumbDinosaur » Wed Dec 12, 2018 12:07 pm

johnpenn74 wrote:
Wed Dec 12, 2018 9:37 am
Sectioning is not allowed with in the same block on the prototype...
Sure it is. Most mainline signals are permissive, which definitely makes it within the realm of possibility that two trains could simultaneously be in the same block.

The permissive concept is intended to keep trains moving. Blocks signals are not anything like highway traffic signals and don't tell an engineer when to stop and when to go, the lone exception being an absolute signal displaying a stop aspect (which cannot be passed). If you enforce a one-train-per-block rule your railroad will get constipated on a busy day as engineers stand at red signals waiting on a slow-moving train up ahead to clear the block.
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rkcarguy
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Re: Signal Complexity

Post by rkcarguy » Wed Dec 12, 2018 1:01 pm

That's kind of the catch 22, you can run permissive signals but then your signal system becomes "advisory" and more of a novelty in my mind than signals to be followed. With an absolute system, it's more "enforcing", but as BDD mentions could clog up a RR under heavy traffic. The only solution is more (shorter) blocks and more signals. Other than the cost, a long train extending into two blocks is going to signal the same in the adjacent blocks no matter how many it takes up, so I don't think that is a big issue. Dividing the blocks into the proper lengths according to train length, and line of sight conditions is all a tricky matter and a lot of thought needs to go into it.

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ccvstmr
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Re: Signal Complexity

Post by ccvstmr » Wed Dec 12, 2018 1:20 pm

Once again...the weak link to most model signal systems is...the operators! Haven't met to many people in the hobby that actually worked for a railroad. Most hobbyists...love trains and railroads, but are not fully familiar with RR practices, rules and signaling. Therefore, keeping a signal system "simple"...ANY type of signal system...will go a long way towards enhancing the experience (and safety) of your club members and visitors alike.

Years ago, had someone at my club develop a signal system. Made a bunch of signal masts...for Pennsy position signals, B&0/C&O color position signals, "normal" 3 aspect signals and maybe one or two other variations. Some signal masts had high and/or low lunar lights. Too many things for members/operators to remember. That signal system was eventually abandoned since it was not immune to wet track and other typical track/signal system issues.

This brings up another point...if there is no "owner" to assume responsibility of the signal system once the originator has departed this green earth...and nobody has been trained to maintain and support the signal system...the hardware will simply be shut off or removed from service. Good documentation regarding signal circuits and theory of signal operation are critically important...if the signal system is going to live on.

Just sayin... Carl B.
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