I have created a layout design that indicates the locations of blocks for both detection and signaling. The single blue lines indicate blocks where the Rail A will be gapped, and the double blue lines indicate blocks where both the Rail A and Rail B will be gapped for power districts. The power district gap location is the point where the lower level double main line tracks meet with the second level of the layout. I have not created the second level blocks at this point, as I wanted to get a indication on lower level first.
Please review the image below, any thoughts, recommendations, or suggestions are welcomed and appreciated.
Looks like you have a pretty good handle on things. Although you may want to subdivide the longer mainline blocks. You’ll be able to squeeze more trains in.
I agree if you divide the longer blocks into 2 you have potential to run 2 seperate trains with 2 seperate controlers on the same length of rail. I’m assuming this is DC of course?[:)]
Since the title of this topic is DCC block detection, I am thinking the layout is DCC controlled… [:D]
The key to block placement is deciding how many trains ther are and where they will be. It doesn’t buy you much to make the blocks so small that your typical train will occupy 4 or 5 of them at once.
One additional thing, if you are thinking CTC type control and want to really have interlocking - a typical double-ended passing siding will actually need FOUR detection sections, not 2 liek it first appears - the immediate trackage around each turnout, including the turnout, is normally detected separately which is used to lock out the ability to throw the switch under a moving train. Since we’re running models here and nothing gets hurt (except maybe our pride if it happens in front of visitors), it’s not required to have real interlocking if you don’t want.
Woops my apologies I guessed wrong and didn’t read the title . Just curious now then why would you want to put in blocks for dcc other than to maybe have seperate power districts or have a seperate program track off the main dcc block of track?
Occupency detection for signals. You still have to break at least one rail to insert a block detection device, even if upstream of the detector it all ties to the same booster. A common method is to run a good-size bus, and then tap off at various points, putting the detector in those taps, which ffeds a short and usually smalle sub-bus, to which all the feeders for that particular section are tied.
Randy, you are correct! It is going to be a DCC system and for occupancy detection you need to have one rail with a gap, as Digitrack calls it “Rail A” to make wiring a bit easier. My interest is to have:
occupancy detection, and
signaling
The transponding, automation, and CTC is not really the scope of my project at this time.
Just a general comment to help you avoid a problem I encountered. The layout I was working with has 12 power districts. All of these have their own power supply (not a power broker unit). I mapped out the signalling districts and simply counted them. I then purchased enough Digitrax BLD168 units to cover that many districts. As I started installing them I read the directions a bit more and discovered that all 16 detection sections on the unit have to be in the same power block. So the block that has 9 signalling blocks will waste 7 circuits. I had to go an buy more detection circuits. So it might not be cheaper buying the BLD168 instead of the BD4 circuits.
The lesson learned is to plan and count the signalling blocks in context of the power blocks.
Are you going to have road crossings, with automatic crossing signals? If so, you might want to plan your blocks so you can use the same ones for railroad signalling as well as crossing signals. If you’re using a computer to run your signalling system, and it’s not convenient to have a signalling block boundary at the crossing, you could have two blocks treated separately to figure out when to activate/deactivate the crossings, but as one for the railroad block signals.
Texas Zepher, Good point you have there. Why did you choose to have so many separate power districts? I am planning on having only two seperate power districts so according to what I have read on Digitrac’s documentation one of the BLD168 units should be able to connect 16 blocks for detection. I have not counted all the blocks as of yet, but it looks like 2-3 of the BLD168 units for the first power district.
[quote user=“Pondini”]
Are you going to have road crossings, with automatic crossing signals? If so, you might want to plan your blocks so you can use the same ones for railroad signalling as well as crossing signals. If you’re using a computer to run your signalling system, and it’s not convenient to have a signalling block boundary at the crossing, you could have two blocks treated separately to figure out when to activate/deactivate the crossings, but as one for the railroad bloc
It is a large layout, with lots of power demands. There are three major yards and nine other towns. It is not only locomotives drawing power, but lighted passenger trains, caboose, and some of the cars have resistor wheels just for the signalling system (I calculated that in one yard, the resistor wheels in the freight cars alone will draw 2.5 amps.). There is a separate power block just for the main steam locomotive facility and another for the diesels. It was also a design feature that a short circuit in one place would not effect someplace across the layout.
That is correct.
The smaller the signalling block the more precise tracking a locomotive with “transponding” will be.
Just some at the moment. The goal is for every car to have at least one axle that is a resistor. The AMP calculation was based on the goal rather than the current state.
