DCC Block Detection
Summary: Block Detection is a method for detecting rolling stock within a given section of track. It is also known as Occupancy Detection.
Knowing where trains are on your layout can be used for many purposes. It can be used for position indicators, operational signaling, automated control, or animation. To perform these tasks, a certain amount of blocking needs to be done for train detection. Even though this does take some work, it's easier to accomplish this with DCC than with block control. While it's not realistic, we'll say that the signal blocks in our example are less than 12 feet long.
To get detection working, you will need occupancy detectors. These are devices that use electronic methods to sense the presence of a locomotive (or appropriately-fitted rolling stock) on a section of track.
There are two basic forms of block detectors. First, and usually the preferred form, is a block detector that detects trains and reports the status to your control system. These detectors are usually more expensive.
The second type of detector simply detects the trains, but requires additional circuitry to send the status to your command station. However, they are still useful without this, as they can operate a crossing gate without the command station even knowing.
Commercial Occupancy Detectors
A number of DCC manufacturers supply detection devices.
Digitrax offers the BDL168 and BD4, as well as the more sophisticated BXP88 and BXPA1.
See Occupancy Detectors for more information.
Preparing the Track
Here are the steps to prepare your track for detection:
- In order to get detection working, you first need to select a section of track you wish to detect if a train is on that track.
- Isolate this section of track by gapping one of the rails at the start and the end of the block.
- Wire the DCC feeds to this section of track via the detector
- Train Detection - Various locomotive and rolling stock detection methods
- Track wiring - General track wiring information
- Signaling - More about signaling
- Animation - Animation control through DCC