Block Detection and Signals


I sure wish someone could direct me to signalling, besides the Santa Fe 1995 (say, back in the '50's) on western roads such as the Burlington Route (pre-merger). My limited understanding is that the Colorado & Southern (C&S...a subsidiary of the "Q") didn't use signals except maybe at interlocking, but relied strictly on train orders! o-o
 
John P said:
I'm finding your use of the term "aspect" confusing. If you look at this page,

http://broadway.pennsyrr.com/Rail/Signal/aspects_us_norac.html

you can see that when they say "Aspect" they mean the appearance of the signal as a whole, and they actually refer to "Aspect(s)" because there are various aspects that can all mean the same thing, and have the same "Name" which should cause the same "Indication". So for Rule 281 they show 9 different Aspects, all of which have the name "Clear", and give the indication "Proceed not exceeding Normal Speed."

So if you talk about "three aspect" signals what do you mean? Context suggests 3 heads, but it could be a searchlight capable of showing 3 colors, which would be correct use of the term "aspect", but that would only be a block signal, not an interlocking signal.

Unfortunately the western railroads don't use pure speed signaling the way we do in the east, where the NORAC rules are most common. I made a quick search for a signal chart that might be used in the west, but didn't come up with anything. Supposedly the western roads use "route signaling" but often it seems to be just a difference in terminology, so under NORAC an aspect of red over green, or green on the middle head of a 3-head signal, or the equivalent with position lights, would be called "Medium Clear" but on BNSF it would be "Diverging Clear". In both cases that's usually what an operator sees when taking a branch off a main line, with a requirement for reduced speed. Maybe someone who really knows signals can say more about this.
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This is why I really have to read up on signalling. As far as I know, It's just red, yellow, green. thanks for opening up the points about signalling.
 
Yes, you do have to get an understanding of what railroad signals do. They certainly aren't the same as traffic lights on roads.

I would say that a branch off a main line into a yard would probably call for a "Restricting" signal, because a train would be entering non-signaled territory and would be governed by sight rules. The distant signal up the line would be "Approach", because the train might be stopping at the yard entrance--there'd be no way to predict that a clear track within the yard would be available. Of course if the yard accepts a train and then makes it stop still blocking the main, the dispatcher would have some angry words for the yardmaster!

For entering staging, the first question would be what that entrance looks like on the railroad. Does the main line simply run into staging, as if it were the "rest of the world"? If so, then no special signals would apply. If it's a branch off the main, then "Medium Clear" or "Slow Clear" would be right, depending on how sharply the branch cuts away from the main.
 
JerryHensler said:
I used this guide when I started the electronics wiring. There are 8 sub districts that are all double gapped. Maybe you can see a difference in how you wired your BDL. Letters are sub district and numbers are blocks within a district.
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Ok, I have been studying your schematic and I have a question about the PM42.
Instructions for wiring the PM42 into the layout is without a BDL168.
If the BDL168 is introduced to the mix, there is the issue with the Detection Common wire from the command station. The PM42 has 4 outputs that would typically go to protected sections of the layout but the BDL168 uses the one common detection rail. How does the detection common wire connect to the track with the BDL168 in the mix. I have attached a schematic of what I think it is supposed to do. The detection common wire comes off the PM42 and is combined again to one wire to the common rail. Is that correct?

Signals_zps3713c254.png
 
JerryHensler said:
My PM42s break the layout in to 8 power sub-districts. Each sub-districts zone common provides the BDLs detection common also in 8 detection common groups. Home run wiring verses whole layout common. The BDLs provide 32 detection blocks. The BDLs are between the PM42s and the A rails only. The common B rails all go directly to the PM42s. The letters A-H (B rails) are attached to the lettered side of the 44 connectors of the PM42s. In your diagram the DS outputs of the PM will feed the inputs of the BDL. The outputs of the BDL will feed the A rail detection blocks. The zone common would remain connected to the PM but with reduced detection capability because of the whole layout common instead of home run wiring. Home run wiring runs separate zone common wiring back to the PM. Multiple boosters and sub-districts require double gapping at zone junctions for best practice type capability's.
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Ok, the diagram that I provided is a home wiring version as I will have two other BDL168s on the layout with their own PM42s.
 
JerryHensler said:
I looked at your diagram again. You did not label the BDL. The detection common for the 4 BDL detection blocks would only go to the PM A zone B rail terminal. Do not tie all the commons together on the PM42. Use the same zone as for the 4 BDL blocks. DS1-4 are in zone A. 5-8 zone B, 9-12 zone C, and 13-16 would be zone D. When the zone commons are tied together, the BDL can't tell if the blocks are empty properly and will default to all occupied as a precaution.
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Ok, I fixed the schematic to show what I think is the correct common wires and detection sections. Is this correct now?


Signals_zpse0923c76.png
 
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this is such a painful process. I am installing the PM42 with the block detection system. One of the things necessary is to isolate the rails so there is no link between zones. I had already wired the section I'm working on with the common rail B wired to one rail of all the tracks in the section. Now, the PM42 requires the rail B to be isolated between zones. Do ya think I can do that in a short matter of time. No way. I have to spend a week tracking down an elusive link between the common rails. Today I completely cut every common rail lead from the track to the buss and guess what. Still shows a link. The tracks are two inches apart! I could not find a single link between them, until crawling under the bench work, I spotted the edge of a wire lead that was soldered to the common wire and linked to both rails. It had been pulled into a hole I had drilled through the plywood and 2x4 when I was adjusting the buss wires. Now, I have to go back and solder some 60 drop wires back to the buss wires, because just one was invisible.
This kind of stuff is what takes the fun out of this hobby.
 
That's what I'm really looking forward to. It's what keeps me going despite all the frustrating circumstances. Even trying to use basic trouble shooting steps by dividing the problem into halves hasn't been working here. I had to disconnect almost every track connector and cut every common rail wire before I found the problem. It's just short of having to pull the track up off the road bed every time I try to do something here.
 
Have had a few days of smooth work flow on the layout with no ellusive faults, tools gone invisible or mix up in wires. I have just a few more solder points to complete the isolation of two tracks into separate power districts and detection zones, (4 blocks per zone). When that is finished I can complete the installation of the PM42 then the BDL168 then venture in to the SE8C and the actual signal heads.
 
JerryHensler said:
Good job! How do you intend to send the SE8 commands? Software or manual commands via throttle?
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I haven't reached that point yet. I think I will probably run it with Digitrax but I also have a laptop I have been prepping to run JMRI for this.
In the back of my mind I'm wondering how the different signal displays are programmed if I'm using three color heads.
 
JerryHensler said:
JMRI has Panel and Layout Pro which can automate turnout control, signal control, etc. I tried it but could not learn the Logix part which is what runs everything. I will use TrainController software when the time comes. It appears to be easier to learn.
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As I haven't got to the SE8C so I'm not really sure how the signal lights follow the train.
 
If I was going to use signals and needed software to run it, since I'm not anykind of a programmer, I'd have to go with the program that makes it a lot easier.
 
JerryHensler said:
The bronze $139 will run the signals.
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Now that sounds more paletable. Oppps, just checked on it. That is the price of the Bronze package. Silver is over $400. It lists a lot of capabilities that I'm not familiare with and it doesn't specify if it works or how it works with Digitrax.
 
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Ok, I have the first block all wired through the PM42 and the BDL168. It is a run of track, about 110 feet from end to end and broken down into four detection sections. There are two turnouts involved so I'm not sure how that will effect it. I haven't powered it up yet because I want to recheck my work tomorrow before I try to run it. If all is good, then I will press on with the SE8C.
I've been reading up on the JMRI signal control system. Pretty complex, but then, I didn't have the program running on my machine to actually see the functions.
 
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