I am working on figuring out signaling for my layout. In looking at the photo below I want to protect the passing siding in the second picturer with the white pushpins heading in both directions. On the right it is entering into a switch, to the left is the balance of the siding. Would I use a single mast with a signal head facing in both directions here (thinking where the S with the arrow is)? If not how would I signal it?
Also would it be prototypical for the train to be stopped on the switch waiting for a green to continue down the siding or would it be stopped some distance before the switches? The first photo shows the entire area in question.
Hopefully these questions make sense, I am just starting to learn enough to even know what questions to ask. Thanks in advance!
Depends on whether you want to be prototypical or you just want lights to indicae which way the switch is thrown.
Assuming the two through tracks with the crossover are main tracks, There would be a signal on each of the two main tracks, at the points of the rightmost switch in the crossover. At the “E” near the pliers that would be 4 signals, one for each of the 4 tracks. The angled track and the siding would both probably be dwarf (low) signals and the two on the mains would be full sized masts.
All the signals on the right side would face a train moving right to left and all the signals on the left end would face a train approaching from the left.
I normally wouldn’t quibble with anything Dave H. says, but if that angled track is an industry spur, the switch would probably be manually thrown, and outside of the interlocked signals. So the signal could be located between the switch points of the spur switch and the crossover. Three signals for trains approaching from the left side; mast signals for the top two mains, and (probably) a dwarf for the third track - but it can be a full signal too.
This of course still assumes you’re trying to do a “proper” realistic interlocking controlling crossovers, and not just switch-position/route indicators for all the switches.
I agree but he never said what any of the tracks were other than the “siding”. If he redefines the tracks to different things or says he isn’t doing CTC it changes the whole arrangement.
You’ve asked a fairly complex question which would require a fairly complex response to answer fully (particularly in writing). Both Dave and Chris addressed the issue faithfully. My rambling answer is also a faithful response . . .
The first thing to ask is do you want to be prototypical, or simplistic enough and practical for model railroading?
The way I understand signals is that they indicate three things: 1) the position of the switch, 2) occupancy of the next block ahead, and 3) occupancy of the following block after the next block ahead, and 3a) the position of the any switches between 2 and 3. These indications would be shown on two sets of signal heads facing both directions. The technical term for these signal masts, signal heads, and occupancy detectors is a signal plant.
Looking at your overall first photo . . . for left-to-right traffic with the train standing about where the white pushpins are, the ‘next’ block of the through track is only about as long as the little yellow tray holding track joiners (Dave overlooked this, which is practical for model railroading). The next following block for the diverging track is about the same length and is the short section between the crossover turnouts. And then the condition of the following blocks for each route and the position of the switches in between goes beyond the limits of the photo. The right-to-left traffic signals are similar, but understandable if broken down and addressed one thing at a time.
The logic of whatever software you use to set the indications on the signal heads of your system would take this into consideration and turn on/off red-yellow-green lamps in the signal head. This is prototypical. I would suggest you go with the simpler system.
This is good. The track plan helps. Dave’s sketch pretty much captures the essence of the situation, but will need to edit one of the stub tracks. Here’s a rough sketch as I see it. Your track plan has a vertical aspect, but the horizontal aspect is easier to see on my screen. Apologies.
Now, what software and/or electronic stuff will you use?
I also use JMRI and Digitrax, but I don’t know if I have enough knowledge to solve this situation. I did kinda well with the mainlines and sidings on my layout, but I pretty much chickened out in the complex yard areas. For those tricky issues, I simply used dwarfs to show position of the switches and let the dispatcher and/or conductor/engineer teams look ahead and pick their way through the minefield one signal at a time. But I will stick around and offer whatever help I can, even if it is only encouragement. There are guys here that know a lot more than I do. There are also some electronic and arduino guys who might be able to come up with a unique little one-of-a-kind gizmo for your intersection.
I think this can be done using short or tall signal masts with only a green “Go” indication and a red “No go” indication. Is your plan to treat all six tracks and all four signals as a single interlock? That is, can there be only one green “Go” signal with all other signals showing “No go” red, allowing a single train to pass entirely through and come out safely on the other side?
Tracks A through F can be considered as blocks, and Digitrax has detectors to indicate occupancy. There are also undesignated (and undetected) blocks between turnout 1 and 2, 2 and 3, and 3 and 4, and JMRI would want to know their occupancy status to determine the logic. We can ignore those three blocks for convenience (model railroading), but if we do I don’t know how to inform the JMRI logic. There are also additional blocks to the left of A, B, C, and D and to the right of E and F that JMRI would be interested in, but we can ignore those for the purpose of this exercise.
This might come down to the dispatcher providing the logic by visually inspecting the occupancy (from Digitrax block detectors and lit on his screen, or just by eyeball) and then manually setting the red/green aspects of the signals. Workable, but not too elegant. Semi-automatic.
Yes. A train heading left on Track E doesn’t care whether Switch 1 is thrown or not, it can traverse the turnout safely either way; providing that Track A is clear. Likewise, the alignment of Switches 2 and 4 doesn’t matter (but Switch 3 does). A train heading right on Tracks A, B, C, and D need to know the position of Switches 1, 2, and 4 (Switch 3 doesn’t matter; providing that Track F is clear) to safely traverse the turnouts.
I need to protect direction of travel both ways on A, B, C
Lets suppose that turnouts 1 and 2 are aligned for a train headed to the left to access track B BUT there is a train stopped on B then I would need a red on B for trains headed to the left. That signal needs to be on B side of turnout 2. So the question is would I use a single mast with a signal facing each direction at the entrance to B? Is there such a thing or would there be a different way of doing it?
I wish I were a better writer or a clearer thinker to explain this. Some of this is explained in the manual for the Digitrax SEC8; and like all Digitrax manuals, it reads pretty much like Mah Jongg instructions.
All signals on my layout have two heads (except the dwarfs mentioned earlier), and all turnouts have two signal masts, one facing each direction. In all cases, the top head indicates the through route of the turnout and the bottom head indicates the diverging route.
From the facing side (the single track) of the turnout, both top and bottom heads have to be read simultaneously. From the trailing side (two tracks), either the top head or the bottom head (depending on which track the train is on) needs to be read. On my layout, the trailing signal mast is positioned between the fork in the tracks, and the facing signal sits on either side of the tracks (whichever is clearer of scenic obstructions). This could be made simpler by using overhead truss support or overhead cantilever supports of the signal heads.
The SEC8 has ribbons that send aspects to both the leading signals (both heads simultaneously) and the trailing signals (each head individually) as explained in the aforementioned manual. The JMRI logic determines which light (red/yellow/green/flashing yellow) on which head is lit.
Based on the new information, here is how the prototype would signal the location (R= remote switch, M=manual switch):
Obviously you have compressed things more that the prototype would, which complicates things.
The question becomes, what do you do with the leaving signal out of the siding?
If you move the signal to the left of the switches, then you are going to need a signal leaving each track really complicating things. Or you could move the leaving switch up next to the frog on the siding switch.
For a movement to the left assuming no other trains:
Main track normal = G over R
Main track reverse, siding for siding = R over Y
Main track reverse, siding for industry = R over Lunar
Yes it does make a difference. Lined normal (A to E) it will be a clear signal. Lined diverging it will be a a more restrictive signal such as a diverging or medium signal.
From a prototype perspective it’s the opposite of what you have said.
If switch 2 is lined for the siding, assuming the siding is “bonded”, has detection in it", if switch 2 is lined for the siding, signal A can give an indication better than restricting. If switch 2 is lined for the industry tracks the best indication it can give is restricting and it doesn’t matter how the other tracks are lined.
Thanks . So how would the crew handle the manual switches? Would the conductor manually inspect the switches to determine how they are lined? Assuming the train where taking the diverging side off the remote switch the train would need to stop to determine how the other switches were lined, and/or change them?
cv wrote: “I normally wouldn’t quibble with anything Dave H. says, but if that angled track is an industry spur, the switch would probably be manually thrown, and outside of the interlocked signals”
Back when I worked Oak Point Yard (South Bronx) in the 1980’s, there was a customer that received cars of flour in the Woodlawn area (north Bronx).
The switch to their (short) siding was within Woodlawn interlocking limits, where the New Haven line joins the Harlem line.
The switch was hand operated, but there was a low signal governing movements from the spur track back to the main track.
You didn’t need a signal to open the switch, you were already inside the interlocking limits. But after you placed the car at the bakery, the dispatcher would display the signal for you to come out of the siding and BACK INTO interlocking limits.
I recall it as being underneath the 233rd Street bridge (which crosses right over Woodlawn). After 40 years, it’s almost certainly gone now.
Yes, the crew would manually get on the ground and manually line the manual switches.
Switches are required to be left in the “normal” position, typically for straight away movement. The switch into the siding would be left lined for the siding.
A train heading into the siding would get a a diverging or medium speed signal at E. That would tell them the switch was lined for the siding and they wouldn’t stop to line that switch because it would already be lined for the siding.
If the switch to the siding was lined toward the industry tracks, reversed, the signal would display restricting which tells the crew to proceed prepared to stop short of obstructions or switches not properly lined. They would know that they have to line switches or be prepared to stop and line switches.
