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Thread: Which Signal - entering a mainline?

  1. #1
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    Question Which Signal - entering a mainline?

    Which signal should be used when entering a two-way mainline? If this was an automobile you would look left and right but I can't get a signal to look both ways at once. Or, this is an irrelevent question since it never happens in a real railroad.
    Regards - Dick
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  2. #2
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    Yeah,

    Trains don't work that way, no steering wheel, yet.

    Normally you would use the 1T for that.

    Pike

  3. #3
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    Before I give up on that one, I meant that a mainline train could be approaching the switch from either direction. A train entering the mainline, from the siding, would need to "look" (via a signal) in both directions for traffic, granting that the siding train could only enter the mainline in one direction but could get smacked from either. Seemed logical to be but .....
    Regards - Dick
    i5 2500K$ 4.2ghz, GTX 750 2gb, 8gb of SkillFULL memory, A 700 watt power thingy, lots of cables
    Program to take screenie weenys from da puter. Bro, Dude, Man operator Murysville,Pa.



  4. #4
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    If it were that easy...

    You don't need to look both ways because you aren't allowed to enter that section of track without permission from someone and even then you are only allowed to be there for a certain amount of time.

    Signals are not like traffic lights controlling the flow of traffic. The dispatcher controls the flow of traffic. The signals just report the states of the junctions in front of you and the occupancy of the track in front of you so hopefully you don't run into anything. Someone running in to you is out of your control.

    Pike
    Last edited by pikehkr; 07-18-2009 at 05:20 PM.

  5. #5

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    I thought that railway track sections are segregated into blocks and if such a block is occupied by a train then no other can enter it and signals of tracks merging into that occupied by a train block would be RED until the occupied train has moved out of it.

    Is that not how signaling works in the USA too ?

    O t t o

  6. #6
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    Yes, that is how they work.

    Just because a signal is not red does not mean you have permission to go there. That is all I am saying. It just isn't that simple. You probably won't run into anyone but you might take a train up the caboose.

    Pike

  7. #7
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    Quote Originally Posted by pikehkr View Post
    If it were that easy...

    You don't need to look both ways because you aren't allowed to enter that section of track without permission from someone and even then you are only allowed to be there for a certain amount of time.

    Signals are not like traffic lights controlling the flow of traffic. The dispatcher controls the flow of traffic. The signals just report the states of the junctions in front of you and the occupancy of the track in front of you so hopefully you don't run into anything. Someone running in to you is out of your control.

    Pike
    That second section is extremely important to someone (like me) that is totally unfamiliar with the philosophy of signals. I believe that my task is to study the several good signaling docs I have found on the Internet. Messing around with a 2-head 2 track signal at a crossover really told me a lot. While trying various combinations I was ready to send a "gotcha" message to Rail Simulation. But, once you begin to think about what the signals designer wants to tell the engineer it becomes clear that a certain link placement is not logical. Somewhat as you described above, entering a two-way track from a siding. In that case, as you said, the only info the engineer needs is that his/her path is, or is not, blocked at some point. Even thinking about LUA scripting at this stage is very premature. Off to the signaling info that should tech HOW to install signals.
    Regards - Dick
    i5 2500K$ 4.2ghz, GTX 750 2gb, 8gb of SkillFULL memory, A 700 watt power thingy, lots of cables
    Program to take screenie weenys from da puter. Bro, Dude, Man operator Murysville,Pa.



  8. #8
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    Default Route Set vs Block Occupancy

    Confusing two different things here, red signal due to a block being occupied, and red signal due to switch set the wrong way. You enter a mainline via a switch, so on the trailing point of the switch you place a 1H1T signal with the second trip beyond the switch. If the switch is set for the curve and the block is unoccupied, then and only then will the signal guarding the entrance clear. To clear up some possible confusion, a switch is a switch is a switch, whether it's called "facing point" or "trailing point" depends on which direction the train is approaching it from, two trains going in opposite directions for one it will be trailing, for the other facing. Facing means you have a choice of routes, trailing means you're joining a single track FROM one of the two routes.



    Standard way to signal a facing point, linked that way it's green over red for straight, red over green for diverge. Generally called a "home signal". This is how you LEAVE the mainline or stay on it.



    Standard way to link a guard signal, switch is straight the signal on the right will be green, the one on the left red. Throw the switch for the curve and the right signal goes red, left signal green. Assuming an unoccupied block, of course. This is how you ENTER the mainline, no need to look both ways because the trailing point signal for one or the other will have to be red, there's no possible setting that will make both green at the same time.



    Another way is to use a doublehead as an Interlocking, linked this way it will show red over red if the near switch is curved regardless of what's happening beyond the points. If the near switch is straight, this will show green over red if the far switch is straight, red over green if the far switch is curved.

    One thing to keep in mind with all this, there's no actual intelligence in the artificial intelligence and there's an unseen mystery guest - the Path. Imagine a blind guy with a cane who has been given a set of instructions to memorize before he starts down a maze of hallways, he starts walking and tapping his cane, stops when he bumps into a closed door. Another blind guy without a cane is following the sound of his tapping, stops when he bumps into blind guy number 1. That's how the AI trains and the Path work, the AI train knows nothing but the sound of the tapping cane, he's merely following the path. The path is what stops for red signals (sometimes) and other paths with higher priority will set the switches so if they're properly linked the signals will display the proper indications giving the illusion that the AI train actually "sees" the signals. Clumsy, cumbersome, and irritating, but the way you have to work this is to set each AI train with a Priority and then set up the timing so the higher priorities go first. Start a train with a high priority that will pass thru a junction at 11:00, a lower priority train set to pass thru the same junction at 10:00 will stop and wait for an hour if it don't quit altogether and give you "scenario failed to load".
    Attached Images Attached Images
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    • File Type: jpg 3.jpg (87.3 KB, 93 views)

  9. #9

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    Rather you guys than me, I'd never get the hang of this !

    You showing this signaled facing switch which has a straight path, perhaps you can tell me why some signals cause such a switch to divert by default, nobody else has been able to explain so far and I have had to use your SPLIT SWITCH - WELD method to change such a switch's default setting from divert to straight, we had to do in the CSX-Mainline route !

    O t t o

  10. #10
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    Sniper,

    I would agree with you in your thinking. That is how I would think it should work. We would both be wrong.

    In your bottom picture. That is not a valid signal set up and would report as an error. From what I can tell you are not allowed to have 2 junctions between the zero link and the 1 link. You need a special signal to handle that situation.

    In your picture if I were to come in off the left track and stop between the bottom and the top junction and switch the bottom junction back to the main route, I would be invisble to that signal. I don't believe the system would know I was there.

    You have created a "dark" area of track and I think the AI will mess up.

    I believe and anyone can correct me, when you start a scenario the game checks to see where all the assets are and sets the occupancy of the signals. After that, the only way a signal knows if you are in it's block is to pass one of it's links which we did not do. So we are invisible. Sweet!

    Now the AI might see that we are there when it tries to path by us, I'm not sure, but I don't think the signal will.

    Pike

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