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Thread: Which Link for Which Head?

  1. #1
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    Question Which Link for Which Head?

    With a 2Head 3Track signal is the top head always tied to links 0 an 1 while the bottom head is for all other links?
    Regards,
    Dick

  2. #2
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    Link 0 is the base link of the signal and is usually placed where the signal stand or head is located.
    Link 1 as a standard should be the end link for the straight-through path through the junction(s). The other links can vary in what they do based on the signal script.

    The signal heads mean different things based on where they are. You can't apply a single rule to them. The combination of lights on a 2 head signal before a single junction may mean something different than a 2 head signal on a straight length of track in the middle of nowhere. It can also mean something different on each railway. With that said...

    The default for the US signals in the game are:

    When covering a junction(s):

    The top head represents the straight-through path when the links are placed across the junction(s) provided the other head(s) show blocked (red). If the other head(s) show something other than blocked, that represents a diverging path will be taken and now the combination of lights from all the heads provide information to the driver. The more heads, the more information that can be passed. The combination of lights and what information they pass is available in the signal/keyboard layout pdf in the Manuals/EN folder and online.

    In the specific signal you are referring to, the top head represents the status of the #1 link provided the bottom head is red. If the bottom head is anything other than red then it represents a diverging route (not a specific route) and both heads can be used to display information to the driver. Based on the combination of lights you may be able to deduce which path you are taking if there is more than 1 alternate path.

    Pike
    Last edited by pikehkr; 09-03-2009 at 11:57 AM.

  3. #3
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    Quote Originally Posted by pikehkr View Post
    Link 0 is the base link of the signal and is usually placed where the signal stand or head is located.
    Link 1 as a standard should be the end link for the straight-through path through the junction(s). The other links can vary in what they do based on the signal script.

    The signal heads mean different things based on where they are. You can't apply a single rule to them. The combination of lights on a 2 head signal before a single junction may mean something different than a 2 head signal on a straight length of track in the middle of nowhere. It can also mean something different on each railway. With that said...

    The default for the US signals in the game are:

    When covering a junction(s):

    The top head represents the straight-through path when the links are placed across the junction(s) provided the other head(s) show blocked (red). If the other head(s) show something other than blocked, that represents a diverging path will be taken and now the combination of lights from all the heads provide information to the driver. The more heads, the more information that can be passed. The combination of lights and what information they pass is available in the signal/keyboard layout pdf in the Manuals/EN folder and online.

    In the specific signal you are referring to, the top head represents the status of the #1 link provided the bottom head is red. If the bottom head is anything other than red then it represents a diverging route (not a specific route) and both heads can be used to display information to the driver. Based on the combination of lights you may be able to deduce which path you are taking if there is more than 1 alternate path.

    Pike
    Not quite clear on the role of the top head. Does the meaning of the lights on the top head change based upon what links-2 & 3 see? Or does the top head only show the status of the switch and the occupancy of the straight track (using Link-1)? If its meaning is different based upon liinks 2 & 3 then I can see why trains have accidents. The top head, in my view, should be sacroscant and deal exclusively with the straight track. Just tossed this out while I go off to read some signal stuff on the web.

    ================
    First thing I read was that the word indication means what you are supposed to do based upon the aspect. Wow, indication is used in place of a more meaningful word such as action. I ain't ridden no trains!
    Last edited by boleyx; 09-03-2009 at 01:13 PM.
    Regards,
    Dick

  4. #4
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    Quote Originally Posted by boleyx View Post
    Does the meaning of the lights on the top head change based upon what links-2 & 3 see?
    Yes, it does if there are more than 1 head. But I'm not sure what you mean by what links 2&3 see.

    Anyway, the heads do not represent the route being taken. The combination of light colors on the heads tell you what you need to know. It just so happens that Green over Red means I'm going straight through and it is clear to the next signal and that signal is not red. Just like Yellow over Green means something. It does not mean the next signal straight through is red and the next signal on the other track is not red.

    The signal design is just pure economics. We already had a 3 light head, why make a 6 light head when we can just add another 3 light head under the existing one? If we need more we just add another 3 light head under that one, need another?

    A total redesign of the system in a not very economical way but if you want just replace every signal in the US with our new multi-color-light single-unit system! Each light can display 16 million colors and you get 12 of them lined up vertically in each unit. That should cover all your needs forever. That will only be 262 trillion dollars and that doesn't include installation or training and the signal guide will be provided on CD for you to print out yourself. It is only 12,062 pages. Oh, you only have a black and white printer? Well, it just so happens my cousin Sal, sells printers. Amazing, right?



    Pike

  5. #5
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    Quote Originally Posted by pikehkr View Post
    Yes, it does if there are more than 1 head. But I'm not sure what you mean by what links 2&3 see.
    Pike
    This brings up for me a need for a bit more clarification.

    What links beyond Link-1 see. I think that a "Link" represents a sensor of some kind in the real world. So, a Link can see the direction a switch is set to or if a block is occupied or a following/subsequent block is occupied or is under a red status. Apparently there is logic hidden in the railside boxes that can take the inputs from sensors and do different "and/or" setups such as you illustrated.

    I looked at the LUA script for the #3 special signal and wow it is complex. I have not learned LUA so I could not completely follow it. But its sheer length did not encourage me to buy a LUA book. Back to 1 head and only a Link-0!
    Regards,
    Dick

  6. #6
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    D,

    You are trying mix how a physical real world device works with how a virtual computer signal works. When I am writing I am writing about how the signals work within the game. Nothing about links or anything else I'm saying relates to a physical counterpart in the real world and if it does, it is purely coincidental on my part.

    Just to clarify.

    Pike
    Last edited by pikehkr; 09-03-2009 at 06:21 PM.

  7. #7
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    Cool Basic basic

    Basically for a two head signal you should see green over red if the switch is straight, red over green if the switch is curved. Variations depend on what else is happening, but essentially one head or the other will always be red since one route (path) or the other is "blocked", you can't get onto the straight track if the switch is curved so the top head displays red meaning you can't go that way. Other aspects would be, for example, red over flashing yellow means the switch is curved but the next signal on that line is yellow. That's the way it's SUPPOSED to work, as Pike says even if you use the correct signals with the correct links they don't necessarily work correctly in this game. Following screenshots are from RS rather than RW, like I said in the other thread I can't get any work done with the blasted thing crashing on me every five or ten minutes so I've shifted back to railsim for route work.



    For this I'm using a 2H3T 40/40, two secondary routes and one primary route, if either of the switches are curved it would show red over green, if both are straight then it can trace the connection from link zero to link 1 and display green over red. Actually for either curve it SHOULD show red over yellow because the next signal on either path is red or flashing red, but it's not reading them for some reason.



    What I did here was dragged the selection tool over the station tracks to change them to yard type and speed limit 10/10, when the secondary link is on a track section with a 15mph or less speed limit it shows flashing red. The 1H0T don't work for that, so I used a 1H1T with both links on the same track. For the ones with switches I used a regular 2H2T, that shows red over flashing red for curved, flashing red over red for straight. Should make whatever the next signal before display yellow or flashing yellow instead of green, dunno yet why it don't.



    This is an interlocked crossover, in real life the switches themselves would be mechanically or electrically interlocked so they would both throw at the same time. Don't work that way in the game, but by placing secondary trip 2 beyond the base of the opposite switch you can interlock the signals. This setup will show green over red if the near switch is straight, red over green only if both switches are curved. If the near switch is curved and the far one is straight then;

    1. The points of the near switch (being set curved) block the trace from link 0 to link 1, top head red.
    2. The straight points on the far switch block the trace from link 0 to link 2, so the bottom head is also red.

    Red over red means don't go, gotta reset one switch or the other to get one of the heads to turn green.



    For this one, being a short distance between trailing point switches, instead of using two 1H1T signals I use one and place secondary trip 1 beyond the base of the second switch. A train coming from this direction would be unable to proceed if either switch is curved and there's no conceivable reason why he would need to go onto that short section of track and stop, so to go he needs both switches straight, which is the only condition that will give him a green. In fact, after placing and linking the signal on the right for the curved track (linked similarly, except that one required first switch curved second switch straight for a green) I moved further back;



    And interlocked that whole stretch. If S1 is curved then S2 also needs to be curved so he gets red over green, if S1 is straight then he needs S3 curved and S4 straight to get green over red. Again no conceivable reason why he would want to or need to stop on a section of track that short, so might as well interlock it.

    As Pike also mentioned, in addition to the track configuration governing how signals are set up, you also have to consider what you're gonna run on it. Where I grew up the Chicago & NorthWestern ran high speed passenger, commuter, and low speed freights and they had block signals about every mile on the mainline. The Chicago Transit Authority Lake Street Elevated ran parallel to that, much higher traffic volume and about the same speeds, but since the maximum train length was 8 cars (and being lightweight electric railcars every axle is powered so they got some serious dynamic brakes) they had block signals every quarter mile or so. Downtown in the Loop the block signals are closer together since there's higher volume and closer following distances, but they also move a lot slower downtown. It's all kind of like deciding how long to make your passing sidings, how long do they need to be? I dunno, what's the longest train you anticipate running on that line? If the railroad only owns one engine you don't need passing sidings or signals for that matter.
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  8. #8
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    A signal covering three routes should have three heads, one linked to each route. I don't think I've ever seen it done any other way.

    In addition, there's a possibility of "no route" if the double slip is thrown for the other route also. Think of it this way, you're going into the intersection, with the double slip set to diverge. That means that the double slip is also set to diverge from the cross track onto your track. If you get Red over Green, the other train also gets Red over Green. If you both try to take the two routes through the double slip, well, two physical objects cannot occupy the same space and time...

    So. Your signal not only has to check the switch state, but also the occupancy of the cross track, much as it would on a simple crossing. So, in your scenario, a main crossing two other tracks connected with double slips, you actually have five different choices: Straight, straight-diverging, diverging, 1st crosstrack occupied, 2nd crosstrack occupied.

    I'm pretty sure a script could be written to account for that, at least in MSTS, it could be done, but I don't know if it could be done in RS.

    Either way, it won't be pretty...

    Strangely enough, I've never seen a picture of double slip switches signaled or within signalled interlockings. They're always part of a yard, and either use dwarfs that only show the route and not occupancy, or non-signalled, with movement controlled by a yardmaster.

    Someone else might have better information though, just because I've never seen it, doesn't mean it isn't done. I have read that they are never used on the main line, only in yards, due to their complexity and fragility. In actuality, the way the real ones work, you couldn't line two different routes through it at the same time.

    If you study this picture, you'll see why. The ones in the game don't work right, neither do the ones in MSTS.

    Robert

  9. #9
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    Talking As if the poor guy wasn't confused enough already!

    Well, few points;

    1. They do have a 3H3T signal which SHOULD work the way you're talking about, except it either don't work or I'm not linking it right, the middle head stays red either left right or center, so I get green over red for straight, red over red over green for left, red over red over green for right. This is all on three way switches I tried those, and figured if the middle head ain't gonna change I might as well use two.

    2. They do somehow sort of when it works have some way to restrict crossings to one path at a time, see this;

    https://www.trainsim.com/vbts/showthread.php?t=285540

    3. All these puzzle switches are restricted to low speed anyway with the 20 meter radius curves, so I was intending to just use dwarf shunt signals on most of them. However;



    Patched that together from 3 pics out of http://www.bing.com/maps/ it's the Western Avenue interchange in Chicago. Used to be C&NW Milwaukee IC PRR NYC and assorted other railroads, probably all belongs to the Union Pacific nowadays. As you can see from the bare patches there used to be more tracks, but some of those are diamonds and some are single or double slips, linked to assorted signals on the signal bridges. When I was a kid it looked really exotic cuz the C&NW was still using semaphores, so the signal bridges had a mix of semaphores, standard 3 light color signals, and the Pennsy position light signals.

    EDIT: Here we go;

    http://www.cnwhs.org/memberphotos/di...lbum=10&pos=17
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  10. #10
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    I guess the key to that whole picture is the signal tower. Doubtlessly, those signal heads are controlled from within the tower. The Tower operator gets his instructions on where the train is supposed to end up at from where it's at, drops the signal to Red, and then sets up the route. When he's sure he's not sending a Milwaukee-bound train to St. Louis, he locks the route, reaches over and flips the signal to Yellow. I highly doubt they have a Green indication at all. It would be kind of redundant, and so would Restricting, since you have a 10 mph limit.

    Then when the train passes, he would throw the signals back to Red, and sit back, drink coffee, have a nice cigar, and wait for that St. Louis bound train to show up, and do it all over again. I highly doubt that those signals are ABS, or even automatic, there's simply too much complication.

    Now, having said that, and realizing that the signals in RS/RW are decoration anyway, I'd guess you could simulate that pretty easily, just by having a R/Y signal, or the R/Y/G if you wish, and doing what you're doing. But at that point, I would just use a single head signal, and if the route is open, you're Yellow, and if the route is closed, or has any interruption at all, it's Red. Not very good logic, but hey, they're just Christmas Tree decorations anyway. Might as well just have them change randomly.

    Now, if I were going to set that up for MSTS, I would build one great big signal for the whole mess and tie it all together so that only one track could be green at a time, even though that wouldn't be entirely accurate either, but it would be closer.

    Speaking of exotic, I have a really cool photo of a three head signal, that apparently started out with three searchlight signals. Then one of the other ones got broke, so they replaced it with a two light colored signal, and then the other one got broke and they replaced it with a modern snowhood three light signal. So, top to bottom: Old looking searchlight, three colored snowhood head, two colored regular visored head. Oh, and it looked like at least half of the ladder had been cut off and replaced with another one that was slightly wider... I always wondered what happened to the poor thing...

    Robert
    Last edited by rdamurphy; 09-04-2009 at 06:33 AM.

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