DCC train detection

Hey all,

I am curious how one can do train detection using a layout board with multiple trains running. What I wish to do is have a block show on one panel a blinking led for that operators train while on the next panel it shows operator #2 a solid and shows that operators train as a blinking led. Any suggestions?

Sent from my SM-G920P using Tapatalk

 

First, you need 'blocks', sections of track where you desire to know where they are. In some areas, lots of blocks, maybe only 12" long while others are many feet. Detectors are put in rah of these. These can be connected to any number of boards that support block detection.

Here are the issues. 1) you need either resistive wheels or relegate it to only the loco's to be able to sense within the block using any manufacturers block detectors or 2) use Digitrax Transponding locomotives with LocoNet based block detection. Having more than one loco in a block knocks you right up to Dixitrax's Transponding decoders.

 

I do have blocks set up. Its a matter of going from analog to dcc.

Sent from my SM-G920P using Tapatalk

 

What system are you using? If you are using Digitrax, the discussion above is valid. If you are using Lenz of other system that supports Asymmetric DCC, there is no need for transponding if the decoders also support Asymmetrical DCC. Digitrax did not the last time I used them. I now use mostly use Zimo, ESU and Lenz decoders now, all of which support the Asymmetrical DCC. You still want to to setup power districts, or Blocks using DC terminology. Ideally the circuit breaker you use on the power district can setup the drive circuit to illuminate an LED when the power district is occupied. The DCC Specialties PSX units can do this, as can others.

 

Digitrax

Sent from my SM-G920P using Tapatalk

 

Umm, asymmetric DCC has absolutely nothing to do with train detection. It can be used in conjunction with detection for automating certain functions on the layout, but it does not have anything to do with the detection. Asymmetric DCC is all about train control, not detection.

 

You can use block detectors as mentioned above. As an example of what is available see the Team Digital DBD22 or BlocD8; also the NCE BD20. These detectors have a coil that the feed to the track passes through to sense the current being drawn. They don't cause the voltage drop that detectors like the Digitrax BD4 do.
Making resistor wheel sets for rolling stock isn't that hard. I glue surface mount resistors to the axle (metal wheels are a requirement) and use a marker with conductive ink to make the connections. I got the procedure off Trainboard, I think it was in one of Jim Reising's posts but I could be wrong.
As far as dealing with multiple trains in one block, the easiest solution to this is to make the detection blocks small enough that this won't occur. My detection blocks are usually no more than two to three feet long.
Personally, I don't like the Digitrax transponder decoder method of train detection. It limits your detection to only working with Digitrax decoder equipped engines. This is a personal opnion and you will get a lot of arguments, but I don't think Digitrax makes the best decoders, so I would not standardize on a detection system that allowed for nothing else. It also does nothing to deal with the situation where the end of the train is in a different block than the engine. I think you would have to put a transponder in the rolling stock, which seems way more difficult and expensive than resistor wheel sets.
If I had sufficient funds I would use a Zimo system with their MX9V detectors. If you want to get an idea of what DCC is capable of read some of their system capabilities.

 

Should have been more clear, if you use the PSX devices, they can drive LED's to show occupancy. Transponding is used to identify the DCC address of the unit in the power district. Asymmetrical DCC allows for the deciphering of the address to be broadcast instead of using RF chokes to sense the address like the BDL board does.

 

Maybe you're thinking of RailCom, because asymmetrical DCC does not give you the address.

The last I checked, the only thing you could do with RailCom is display the address of a loco in a block - although planned, unless it has changed recently there is nothing available to feed that address back into the DCC system for any kind of responsive control.

Edit - I did another search and there are now RailCom modules for reporting address back to the DCC system. As far as I can see, these are only available for ECoS DCC systems.