dehusman gregc my basic understanding of signaling is to position signals at either end of a siding used to allow trains to pass one another on a single track mainline. One thing that would provide clarity is the era and method of operation on the main track (TT&TO, TWC, DTC, Rule 251). The basic premise, above, is misunderstood in ABS. The positions of signals in ABS are such that they provide protection for following and opposing moves. What determines where a train meets another train, when it can leave the siding and who is in the siding and who is on the main has nothing to do with the signals in ABS. All of that is determined by the rules, the method of operation and what the authorities given to the train say. In ABS, the block signals never tell a train to head into the siding. The signals never tell a train to leave the siding or a meeting point. The signals control the speed of the trains in the block and tell the trains to look out for something in the block. They tell the train how to proceed, they don't tell the train when to proceed or give the train authority to proceed (except in Rule 251).
gregc my basic understanding of signaling is to position signals at either end of a siding used to allow trains to pass one another on a single track mainline.
One thing that would provide clarity is the era and method of operation on the main track (TT&TO, TWC, DTC, Rule 251).
The basic premise, above, is misunderstood in ABS. The positions of signals in ABS are such that they provide protection for following and opposing moves. What determines where a train meets another train, when it can leave the siding and who is in the siding and who is on the main has nothing to do with the signals in ABS. All of that is determined by the rules, the method of operation and what the authorities given to the train say. In ABS, the block signals never tell a train to head into the siding. The signals never tell a train to leave the siding or a meeting point. The signals control the speed of the trains in the block and tell the trains to look out for something in the block. They tell the train how to proceed, they don't tell the train when to proceed or give the train authority to proceed (except in Rule 251).
In ABS single track territory, a green signal doesn't necessarily mean you can go. A red signal doesn't necessarily mean you have to stay.
Jeff
gregcmy basic understanding of signaling is to position signals at either end of a siding used to allow trains to pass one another on a single track mainline.
Dave H. Painted side goes up. My website : wnbranch.com
BRAKIEA dispatcher is paid to know where the trains are at on his section of railroad and direction of travel or being held in a siding as you should know.No dispatcher would be ignorant enough not to know since he is responsible for that section of track.
Dispatchers do not know where trains are in dark or ABS terrritory unless the train crew or an operator tells him. There is NO system in dark or ABS territory that tells a dispatcher which switches are lined or where the train is. he knows what he authorized but doesn't know where the trains are. Even in modern TWC and DTC, the dispatcher knows what section of track a train is in and he can have a rough guess on where it "should" be, but he doesn't know where it actually is, unless the crew, or another train, or somebody else tells him where they are. If there are hot box detectors that announce a train's presence over the radio, he might hear the HBD announce something passing over the detector and figure that was the train but nothing actually tells him that is the train.
In TT&TO, the train could put out flags and be doing all sorts of stuff, and unless the crew, or another train or the operator tells the dispatcher what's going on, he would never know.
dehusman BRAKIE I don't know of any dispatcher that would allow a runaround move if either block was occupied. If its ABS, how would he know? The dispatcher wouldn't have any idea whether the train was standing on the main when it was run around or was in the siding.
BRAKIE I don't know of any dispatcher that would allow a runaround move if either block was occupied.
If its ABS, how would he know? The dispatcher wouldn't have any idea whether the train was standing on the main when it was run around or was in the siding.
A dispatcher is paid to know where the trains are at on his section of railroad and direction of travel or being held in a siding as you should know.No dispatcher would be ignorant enough not to know since he is responsible for that section of track.
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
dehusman BRAKIE I don't know of any dispatcher that would allow a runaround move if either block was occupied. Actually the only way a dispatcher can "authorize" a runaround is in Rule 251 or one of the modern systems like TWC or DTC. In TT&TO there really isn't a mechanism for a dispatcher to "authorize" a runaround in ABS or dark single track. The train crew would make the move by flagging.
Actually the only way a dispatcher can "authorize" a runaround is in Rule 251 or one of the modern systems like TWC or DTC. In TT&TO there really isn't a mechanism for a dispatcher to "authorize" a runaround in ABS or dark single track. The train crew would make the move by flagging.
There is no flagging today with two men crews so a dispatcher would need to know.
oops!
7j43kOn a different note, recall that Dave keeps mentioning "lunar", and I don't. There were (and are, I guess) different rulebooks for different railroads.
There are hundreds of rules books issued by many railroads and groups of railroads, with different versions issued every 10-20 years. Some changes and variations are minor, some are significant in wording, most are pretty much the same when you boil down to the intent of the rule.
I was trained on the 1968 UCOR and the 1985+ GCOR.
As you can tell by the title of the one I quoted, there was consolidation of these rules.
The North American railroads, through the AAR developed a generic set of rules. The railroads modified them to meet the specific needs and policies of the individual railroads. Groups of railroads, often geographically associated railroads, would get together and form a committee to develop a common rule book for the railroads. There were several of these. The UCOR, CCOR were common in the west in the 50's through the 80's. GCOR is common in the west now and NORAC is common in the east. The Canadian and Mexican railroads have their own rule books (there is a separate UCOR that applies to just Canadian roads).
Here's what the above book has to say about color signals: Red: Stop. Yellow: Proceed as prescribed by the rules. Green: Proceed, and for other uses prescribed by the rules. White: Flag stop (See Rule 28) and for other uses prescribed by the rules. Blue: As prescribed by Rule 26 and for other uses. Purple: When used on siding derails--Stop: and for other uses as prescribed by the rules. Lunar: For use as prescribed by the rules.
Red: Stop.
Yellow: Proceed as prescribed by the rules.
Green: Proceed, and for other uses prescribed by the rules.
White: Flag stop (See Rule 28) and for other uses prescribed by the rules.
Blue: As prescribed by Rule 26 and for other uses.
Purple: When used on siding derails--Stop: and for other uses as prescribed by the rules.
Lunar: For use as prescribed by the rules.
These are general signal color definitions, generally applying to color light and flag signals and don't necessarily apply to block signals. There are separate block signal rules that have specific aspects and indications defined.
Red doesn't always mean "Stop". For example in the track diagram provided, in many rule books, there wouldn't be a single "Stop" signal on the entire subdivision. Every one of the signals shown has a number plate which, under many rule books would make them all "stop and proceed" or "restricting" signals depending on era. Depending on era, what you do at a stop and proceed signal can vary. In older rule books, you would have to stop, then proceed at restricted speed at every restricted speed signal. In some rule books from the 1980's-1990's, you would stop and proceed at restricted speed, and then if you encountered another stop and proceed signal while moving at restricted speed, you wouldn't have to stop, you could pass it at restricted speed. In man recent rule books it becomes a "restricting signal", where you don't have to stop, you just proceed at restricted speed. Same signal, three different methods of proceeding, none of them a "Stop" signal.
In ABS even a "Stop" signal (all red, no number plate or an "A" plate) isn't necessaily a Stop signal. In many rule books, if its not an interlocking, and the train has authority beyond the signal, the train should stop at the signal, attempt to contact the dispatcher, if they can't contact the dispatcher, they can pull past the signal by 100 feet, wait 10 minutes, then move at restricted speed to the next signal and be governed by that signal. If they do reach the dispatcher the dispatcher will check to make sure there aren't any conflicting movements, if there aren't, he will authorize the train to pass the stop signal and proceed at restricted speed. In the UCOR that was called a "350-104c" for the two rules that the dispatcher and train crew had to comply with to pass the signal.
In the UCOR a "lunar" signal is actually a "Low" signal Rule 290 and it indicates that a train should proceed at Low Speed:
1. Within ABS- to the next signal in the direction of movement.
2. At interlockings outside ABS- through the interlocking limits.
3. Where this signal governs movement onto a non-signaled track - until entire train is through the turnout.
Option 3 would be the situation heading into an unbonded siding. You can't have a clear into an unbonded siding, because the signal system doesn't know if the track is indeed clear. You can't have a diverging approach into an unbonded track because the signal says to proceed through the diverging route, prepared to stop at the next signal, but doesn't tell you to watch out for other stuff on then unbonded track.
But that's the '68 UCOR. In the '80 CCOR lunar just means proceed at restricted speed. In the '59 CCOR, on the MILW lunar means restricting, on the GN and SOO a lunar means a spring switch is lined normal and the MSTL and NP don't use lunar.
7j43k gregc if a passenger train stops at a depot, what is a station? from "The Consolidated Code of Operating Rules, Edition of 1959": "STATION.--A place designated in the timetable by name." There WILL be a sign at the physical location. That is all that is required. A building may or may not be attached to that sign. My wording of that sentence implies the sign is more significant than the building. For operating people, that's true.
gregc if a passenger train stops at a depot, what is a station?
if a passenger train stops at a depot, what is a station?
from "The Consolidated Code of Operating Rules, Edition of 1959":
"STATION.--A place designated in the timetable by name."
There WILL be a sign at the physical location. That is all that is required. A building may or may not be attached to that sign. My wording of that sentence implies the sign is more significant than the building. For operating people, that's true.
I've seen more than one otherwise knowledgable railroad scholar get messed up due to those station signs when adding a caption to a photo. "The AB&C railroad train takes the side track at Wilson, Wisconsin". Well no, it isn't in Wilson Wisconsin. Back when the railroad built the siding, it was way out in the country. One switch was near a farm owned by a family named Wilson, so they identified it as "Wilson" with a sign. The other end of the siding was by a rock quarry so got a "Rock" sign.
In urban areas, sometimes the station sign takes the name of the nearest street or some other landmark.
There is no definition in that book for "depot".
Keep in mind that the timetable referred to is the employee timetable, not the handout one for customers.
On a different note, recall that Dave keeps mentioning "lunar", and I don't. There were (and are, I guess) different rulebooks for different railroads. As you can tell by the title of the one I quoted, there was consolidation of these rules. And changes over time, as indicated by the Edition date.
Here's what the above book has to say about color signals:
Wow, so much "use prescribed by the rules"! Rule 26, by the way, discusses "Inspection and Repair Protection". So, in particular, it's equivalent to the famous blue flag.
These books are informative reading. You should pick one up for your particular railroad and era. That, and an employee timetable.
The one I've got is for: Milwaukee, DRI&NW, Des Moines Union, DSS&A, GN M&St. L, MNS, Soo, Minnesota Transfer, NP, SP&S, SI, and UP. Pretty much the railroads of the Northwest.
Ed
appreciate some of your earlier posts regarding situations and rules violations. starting to understand.
dehusmanRemember not to confuse "depot" and "station". The passenger train stops at the depot.
greg - Philadelphia & Reading / Reading
BRAKIEI don't know of any dispatcher that would allow a runaround move if either block was occupied.
gregcso what if there is indeed a station. Would there be only a single track next to the station and it would be the siding track described above? What if a passenger train coming from the opposite direction needs to also stop at the station?
Remember not to confuse "depot" and "station".
The passenger train stops at the depot. The depot can be on single track main, it can be next to the siding or it can be next to the main with a siding.
Doesn't matter. The passenger train stops. The signal system works the same whether its a passenger train or a freight.
How it works depends on whether you are operating TT&TO, TWC or DTC. Whether or not there are signals is immaterial. It works the same in dark territory or ABS. The only time it works differently is in CTC or interlocking.
gregcis block 12 occupied if the turnouts are aligned for the siding and the siding is unoccupied?
In most ABS areas I have worked, the sidings are unbonded, that means there is NO detection in the siding. It doesn't matter whether there is anything in the siding or not, the signal system doesn't know because there is no detection. If the switch is lined for the siding the signal displays low/lunar or stop and proceed otherwise.
On many railroads, siding 4 would be a rules violation, because switches are supposed to be left lined normal.
Siding #8 is also an interesting situation. The train is in the siding and both the entering and leaving switches are lined for that train. That means its kinda in the middle of a move. Either its making a runaround move or its been authorized past 8 and the rear end crew hasn't lined behind and the head end crew has opened the leaving switch in preparation to depart.
Siding 12, the train has some sort of instructions to meet a train there and as a courtesy has opened the arriving and leaving switches or has just met a train and as a courtesy is going to get the switches.
gregcA real railroad is not hectic as our operating sessions.
Just don't tell a dispatcher that since his job can be very hectic.
A train crew's can be a day of hurry up and wait especially a local.
thanks Ed.
i have a better understanding of how a real railroad works. A real railroad is not hectic as our operating sessions.
gregc so what if there is indeed a station. Would there be only a single track next to the station and it would be the siding track described above?
so what if there is indeed a station. Would there be only a single track next to the station and it would be the siding track described above?
For the particular station I'm thinking of (Lyle WA), the passenger trains stopped on the main line, right in front of the station. There was a siding on the other side of the main. I would imagine another train could have used that one to pass. But, like I said the platform was on the main.
On the other hand, they COULD have put the station on the siding side. But that means the siding would have had to be clear when the passenger train arrived. Which can be a pain, if someone is working that track. With the Lyle example, above, the "arrival" track is almost always clear, being the main.
I imagine there were many varied track arrangements, all built to be useful.
But. There does not HAVE to be a siding there, at all. Lyle only had them because of "other business". Without that business, they'd be stopping on the main. Of course, under the circumstances, there then might not have been a station at all. Or perhaps only a flagstop.
What if a passenger train coming from the opposite direction needs to also stop at the station?
Remember that passenger trains were, and are, run on a schedule. Which means, in theory, the meets for those trains were planned months ahead. And put in the schedule.
Anyway, if two opposite running passenger trains had to both stop at a station, they did. If it was a regular thing, they would put a platform in on both tracks. If it was unusual, the passengers might not have a platform, and would be standing in the ballast hoping someone from the station would come and get their luggage.
7j43kIn this situation, if the train was there, and the track switches were thrown to the main, the signal at location 12 would be red. That's because the block is occupied, and the detection senses it. If the train wasn't there, and the track switches were thrown to the siding, the signal would also show red. That's because the switches are thrown, and that affects to signal indication.
If the train wasn't there, and the track switches were thrown to the siding, the signal would also show red. That's because the switches are thrown, and that affects to signal indication.
ok, this makes sense. Thanks
I had started to reason that the only time the signal can be clear is if a train can proceed through the block on the mainline track. It make sense that if a train does need to stop at the siding, it should stop in the siding track and align the turnouts for the main.
gregc i tried to illustrate that the block 12 turnouts are aligned for the siding and that the mainline track is occupied. is block 12 occupied if the turnouts are aligned for the siding and the siding is unoccupied?
i tried to illustrate that the block 12 turnouts are aligned for the siding and that the mainline track is occupied.
is block 12 occupied if the turnouts are aligned for the siding and the siding is unoccupied?
Well, there IS a train there. So, yeah. The main line has a detection circuit. It picks up the occupancy and "tells" the signals. You could argue that the signal(s) should be green, because the route goes around the train, and that route is clear. BUT. That's not how it works. Remember, there's no occupancy detection for sidings. So it can't be deemed un-occupied. OR occupied. The "system" just doesn't know. So it can't issue a proceed around the stopped train. In the real world, perhaps the stopped train, knowing that there was an approaching train coming, has the brakemen go out and throw the switches (which may well be a big no-no, I don't know). This will still allow the approaching train to go by, but at an appropriate restricted speed. Which is much better than having to stop.
In this situation, if the train was there, and the track switches were thrown to the main, the signal at location 12 would be red. That's because the block is occupied, and the detection senses it.
Either situation will cause the signal to go red. In this case, BOTH do it.
Keep in mind that the purpose of ABS signaling is to tell nearby trains that a DETECTING block is occupied. And how far ahead it is, based on the display colors. A siding is not one of those. But fairly soon after some smart person got the basic idea down, another smart person said: "Wouldn't it be neat if we pretended that a track switch thrown against the main was a sort-of occupany, ALSO?" So they did.
Not to get too involved and confusing, but rock-slide fences are also tied into signal systems, pretty much the same way. Rocks slide, sensors are triggered, and signals go red. Not because there's a train there, of course. But danger, there sure is.
7j43kIn particular, over on the right with block 12, the signal adjacent to block 12 should be red (as it is) because both switches are thrown to the siding AND the block is occupied.
A couple of points, first:
You don't show the block boundaries. You sort of have them in the middle of each track switch. Doesn't happen. I will assume that the block boundaries are "just outside" the points of the track switch.
Also, there's no way to reference a particular signal. Consider that there is a signal at each end of a block. For any numbered block, there's no way to know which of the two signals is which. So you REALLY should add a way to identify each signal. The block number and the signal identifier are not the same thing. It would make sense to identify each signal with its milepost location, perhaps followed by an E or W to tell which of the two signals at the location you're talking about.
Also note that on single track, each of those signals would, in fact, be two signals facing outwards from each other.
Anyway, all that said:
the signals adjacent to blocks 5 and 6 should both be green, because the track switches are aligned to the main, and the main is un-occupied.
every thing else looks pretty ok, though.
In particular, over on the right with block 12, the signal adjacent to block 12 should be red (as it is) because both switches are thrown to the siding AND the block is occupied. The signal adjacent to block 13 is displaying green because it is unoccupied, and there are no track switches thrown against the main.
I believe I now understand that a signal provides an indication for a block and that somewhere in the block may be a siding. In other words, there is not necessarily a signal just outside a siding.
NWP SWPonce train 1 is in the siding and the switch thrown the block goes green because there's no longer a train in its detection purview
make sense to me
i've tried to illustrate all the cases in the above. Blocks are numbered left to right from 1 to 13. All the even number blocks have sidings. Each siding has a mainline and a siding track. The mainline track is shown in line with the mainline and the siding track to the side (above).
sidings 2, 6 and 8 show both turnouts aligned to the mainline track. Sidings 4, 8 and 12 show the turnouts aligned to the siding track. Sidings 6 adn 8 show the siding track occupied. Sidings 10 and 12 show the mainline track occupied.
i don't believe my logic for determining signal indications is correct. I think 6 and 12 are wrong.
please tell me which signal indications are correct.
thanks for all the help
NWP SWP Theoretically if you have a railroad with say 5 signal blocks there is a train in blocks 1 and 5, the one in block 1 has proceed to block 2, the dispatcher tells them to take the siding, when train 1 proceeds to take the siding it enters block 3 and the signals go red, train 2 stops in block 4, once train 1 is in the siding and the switch thrown the block goes green because there's no longer a train in its detection purview, therefore train 2 proceeds with caution into and through block 3, when train 2 is clear train one exits the siding, is this correct?
Theoretically if you have a railroad with say 5 signal blocks there is a train in blocks 1 and 5, the one in block 1 has proceed to block 2, the dispatcher tells them to take the siding, when train 1 proceeds to take the siding it enters block 3 and the signals go red, train 2 stops in block 4, once train 1 is in the siding and the switch thrown the block goes green because there's no longer a train in its detection purview, therefore train 2 proceeds with caution into and through block 3, when train 2 is clear train one exits the siding, is this correct?
Yup.
Steve
If everything seems under control, you're not going fast enough!
Signaling is hard to get until you suddenly do, and then it's simple. Except for the stuff you still don't get.
gregc my primary question is about a signal for entering block with a siding.
my primary question is about a signal for entering block with a siding.
OK. We've got an ABS signal block. At each end of the block, there's a pair of signals facing each direction. Somewhere in that block is a double-ended siding. I believe you have also added at least one other double-ended siding off of the first one.
My understanding is that the signal should indicate stop if the main (siding) is occupied
No. Because those tracks have no detection. Thus the signal system would have no input.
or if either turnout is not lined for the main.
Leave off the "or". Then you are correct. If either switch is not lined for the main, the signal system will react. In my version, the "out facing" signals go red, with preceding signals going yellow and then flashing yellow. I believe Dave is leaning towards lunar white and some directionality. But the deal is the same, in that: It's the thrown switch that inputs to the signal system, not the non-existant detection on the various siding tracks.
The deal is that ABS is the basic signal system, and it's all over the place in this country. You can get fancier, and people did/do; but it costs the railroad more money. And thus has to be justified.
I like that you are persevering.
You will note that Dave and I don't always say exactly the same thing. I think that is because I am describing basic ABS, and he is describing what I guess would be called "advanced ABS". Pretty early on, it became obvious that you could safely "violate" basic ABS, if you did it a certain way. Or maybe you could say you could "upgrade" basic ABS to be more efficient, without losing any safety features.
Efficiency and safety UP. Always a good thing.
gregc But if there is a signal at each end of the siding, this doesn't seem allowed if the blocks at either end of the siding are occupied (not clear).
I don't know of any dispatcher that would allow a runaround move if either block was occupied.
The local would stay on the siding until the second opposing train past.
gregc sorry to revive this, but am working on implementation for a station siding (not run-around). There's a signal on the main indicating whether it is safe to proceed into the siding. But the siding has two tracks. i believe one way to implement this is that the signal should indicate stop if the siding turnout is in a position to route the train onto an occupied siding track and should be clear/approach if the turnout is in a position to route the train onto an un-occupied track. if true, the signaling system depends on turnout position is this correct?
sorry to revive this, but am working on implementation
for a station siding (not run-around). There's a signal on the main indicating whether it is safe to proceed into the siding. But the siding has two tracks.
i believe one way to implement this is that the signal should indicate stop if the siding turnout is in a position to route the train onto an occupied siding track and should be clear/approach if the turnout is in a position to route the train onto an un-occupied track.
if true, the signaling system depends on turnout position
is this correct?
Hey Greg-
There's an old saying: one picture is worth a thousand words. And there's a reason such a saying is so popular: it's true. Trying to describe your situation in words alone is very complicated and a sketch would really help.
I don't have access to AutoCAD at the moment, so I cannot produce any sketches, but on my layout there are two 'sidings' that seem similar to the topic of this thread. There is a trackplan drawn to scale on my blog and on my layout thread called 'SNSR Layout Build' in the General Discussion section.
There is a passenger station siding on the right side of the layout and a siding that serves Talleyrand Intermodal on the middle peninsula. The passenger siding is single track, and the intermodal siding is double track. Each is about 10 feet long (in N-scale) and can hold entire trains, so they could fall into the 'passing siding' category.
I use Digitrax BDL168s and SE8Cs to detect occupancy and drive signals, and I use JMRI to control the whole shebang. All turnouts are actuated with Tortoise motors. The layout can function completely automatic as ABS or as CTC with a dispatcher setting routes (and throwing or closing switches) and whatnot through a JMRI control panel. The signal aspects are set based on track occupancy for the next two blocks and on the direction the affected turnouts are set. Notice: blocks and turnouts.
Looking at the trackplan, which 'siding' describes the situation you're concerned with? Or, can you whip out a quick sketch? I'm interested to see what you mean by the 'two track siding' phrase I highlighted in your post above.
Thanks, just trying to help.
Robert
LINK to SNSR Blog
dehusmanIf the train is meeting an opposing train at the siding and the opposing train is on the main track waiting for your train, the signal will display stop. Your train can pass the signal displaying stop without talking to anybody in order to head into the siding.
dehusmanThe switch position affects the signal indication.
i think the above two statements are contadictory.
maybe i'm confusing the signals for entering and leaving the siding tracks.
7j43kWhat usually happens is when one of the two siding switches is thrown against the main, the system acts like that trackage is suddenly occupied--reds in both directions, etc.
7j43kTypically, under these circumstances, the red doesn't mean come to a full and complete stop and sit until the signal changes. It means to slow WAY DOWN and be real cautious about what's ahead.
my primary question is about a signal for entering block with a siding. My understanding is that the signal should indicate stop if the main (siding) is occupied or if either turnout is not lined for the main.
i'll leave for later my question about one of more signals for exiting either or both siding tracks onto the main.
appreciate the responses. I think there's terminology in the responses that i don't fully understand.
gregc guess i'm using wrong terminology. by station siding, I should have said passing siding on a single track mainline, turnouts at both ends. and i'm concerned about control of a signal protecting the siding from one direction.
guess i'm using wrong terminology. by station siding, I should have said passing siding on a single track mainline, turnouts at both ends.
and i'm concerned about control of a signal protecting the siding from one direction.
The signals don't "protect the siding". Since this is ABS. There will be a signal on the main track, before the points. Assuming there is only one train out there, a train approaching the siding on the main will have a clear signal. If the train has to take the siding, it will stop and line the switch. If it hasn't passed the signal, the signal will display a low (lunar) signal into the siding. It doesn't matter what position any switches are or whether there are any cars or trains in the siding or other tracks, the signal will display a low signal. There could be an oppising train pulled right up to the clearance point in the siding and the signal will still display a low signal.
If the train is meeting an opposing train at the siding and the opposing train is on the main track waiting for your train, the signal will display stop. Your train can pass the signal displaying stop without talking to anybody in order to head into the siding.
of course there should be multiple signals at either end of the siding and in both directions, both entering and exiting the siding.
Of course that only applies in CTC, NOT in ABS.
i'm also unsure of how siding turnouts are controlled at either end of a passing siding.
In ABS the siding switches are manual.
With ABS, does a turnout position, regardless of whether it is manally switched or not, affect an ABS signal?
The switch position affects the signal indication. A trailing point switch lined reverse (against the movement) will cause the signal prior to the switch to display stop or stop and proceed (and appropriate indications on signals approaching that one). A facing point switch lined reverse will cause the signals to display a restrictive signal, depending on what is beyond the switch (and signal).
[/quote]
Ok. So we're talking about a single track, a track switch creating a parallel track, and another track switch that reconnects the parallel track to the single track.
The "multiple signals" you're talking about are typical of a CTC track with siding. Or. Each track switch is a stand-alone interlocking. Which is very similar. Maybe identical. BUT. This setup is used for high-speed heavy use trackage. I get the feeling yours isn't.
Thus. IF there are signals, they would likely by ABS type. What this means is that the trackage is divided into blocks (THESE ARE NOT NOT NOT THE SAME AS OUR DC ELECTRICAL BLOCKS. Though slightly similar). Whenever a block is occupied, the signals change from green to the appropriate color, starting with red, and "spreading" outwards. The signals don't typically protect the siding in the manor I think you're thinking of. What usually happens is when one of the two siding switches is thrown against the main, the system acts like that trackage is suddenly occupied--reds in both directions, etc.
gregc i'm also unsure of how siding turnouts are controlled at either end of a passing siding. With ABS, does a turnout position, regardless of whether it is manally switched or not, affect an ABS signal?
i'm also unsure of how siding turnouts are controlled at either end of a passing siding. With ABS, does a turnout position, regardless of whether it is manally switched or not, affect an ABS signal?