I have the DCC Specialties Block Watchers on my layout. They were installed with default factory settings. Only the jumper pin was changed to pins 2 and 3. They work as expected with all motive power.

I would like to detect my cabooses as well. I have Proto 2000 wheelsets to which I attached a 10k ohm surface resistor. I completed the circuit with conductive electric paint. The results are good with an ohm meter, but the wheelsets do not detect with the Block Watcher.

Does you have a recommendation for what size resistor I should use? Maybe 15k or 20k? I don’t want to purchase a 100 of them to find out I need something with a different rating. I love the product and the support too.

Thanks in advance, Bob P.

Bob:

The Block Watcher was designed to work with 3.3K resistors. However, before you run out and purchase them, try following the instructions for executing the auto calibration. Depending on your layout, this MIGHT bring the 10Ks in, particularly if you put one on each truck of your caboose (ie 2 axles of the caboose have a 10K resistor). This will give you 5K on the caboose, and a calibrated Block Watcher will trip at 5.6K.

Keep in mind there is a trade off here. You can get the BW to respond to a very small current change, but if it is too small, it may trip based on changes in humidity, etc, because ambient conditions can change the current drawn by the track with no rolling stock present. That is why we designed for 3.3K.