DCC and Radio Control

What we learned in Orlando

By Dave Freshwater

The layout at Magic Rails was three loops, connected by an Orlando NTRAK version of the Diamond Mill, one of our Mountain junctions, and Gordonsville, a oNeTRAK junction. Red Line operations were Radio Control DCC operations. There was one booster in the loop operated by Orlando NTRAK and a second booster for our loop and the Pea Vine oNeTRAK loop.

Testing the Red Line through the NTRAK loops seemed to take as long as in would normally take us to set up for Red Line Route™ operations using the Aristos. Because there are no "screamers" on the boosters, like exist on the Lindsey Three Pack Throttle, it seemed more difficult to troubleshoot a problem. The most useful tool appeared to be an automobile brake light bulb with alligator clip leads. The DIGITRAX folks also used a penny, listening for a hum when you shorted out the rails. That was a lot harder to do in the noisy environment of a public set-up than you might be able to do for a home layout.

Lesson 1: Set up takes about the same time; troubleshooting seems harder.

The most baffling problem on the layout involved polarity. Even though the DIGITRAX DCC operates on AC current, there was a problem with trains entering our loop on the layout. The DIGITRAX folks finally tracked the problem down by running a non-DCC engine into the loop. The analog engine tried to back up as soon as it transitioned between the loops. A connection at the booster in our loop was reversed and the problem was solved.

A few operators "lost" their trains while operating over the Red Line. This may have been the result of the power saving feature of the RC throttles. If there is no power input for a period of time (noted as 3 minutes in a review that I read), the power saving feature kicks in. You have to plug the throttle back into a connection on the layout to regain the train.

There seemed to be a larger voltage drop with DCC operations at the far end of a "power district" than we normally see with Aristo operations. During my Red Line trip, I started out at between 25-35 on the throttle, but had it turned up to 65-70 at the end of the district to maintain the same speed. Then again, we would have probably set up the area of each "power district" as two to four blocks.

Lesson 2: There is a learning curve for the system.

On Thursday, Red Line trains were operated in both directions. That led to some very interesting head to head meets. Friday and Saturday, the Red Line defaulted back to Right Hand Running Rules. While DCC gives you the capabilities to run trains in both directions in the same block, you must have dispatching. Sending out trains of unknown length without knowledge of siding locations and lengths just results in trains backing over long distances.

The layout ran out of engine addresses before the Operations clinic on Friday. Orlando reported later that they had forgotten to program the Chief to make a higher number of engine addresses available. Some clubs have reported on the N-Scale list that they still need to have a Motive Power Dispatcher to ensure that addresses are cleared when locomotives are removed from the layout.

Lesson 3: To take full advantage of the system, more effort is needed to run the layout.

DIGITRAX does not recommend running an analog engine on a DCC line for long periods of time. The motor for the engine constantly twitches as the current alternates. This causes the engine to get warm and, if left stationary for long enough, could cause damage to the engine. DIGITRAX also does not recommend operating decoder equipped engines on an analog loop for long periods of time. In addition, a DCC engine will have a higher starting voltage on an analog line that it would on a DCC line. The decoder will look for its information packet, up to a certain point. Then it will immediately respond.

Lesson 4: You really need dedicated engines for DCC operations.

The throttles were easier to operate than an Aristo, since you didn’t have to reprogram for new blocks.. On Saturday, Orlando allowed the public to take a train around the layout. I know that there was a 4 year old operator who successfully negotiated the Red Line.

Lesson 5: Once operational, our normal operation mode is easier.