DCC

[ken hinrichs]

I've purchased EZ Command and am a novice at this. Here's my question:

If I have a DCC equipped engine moving down a length of track and it passes over an insulated rail junction with wires reversed after the insulators, will it stop, short circuit, reverse....? What do I do if the engine stalls at the insulators.

The dashed lines below indicate one of the two rails of track. "{" indicates an insulator

DCC Command feeding + AC (+) ------------------------------{---------------------------- (-)
DCC Command feeding – AC  (-) ------------------------------{---------------------------- (+)

If I have two parallel tracks with opposited polarity (ie., outside rails are positive and inside rails are negative) and use two insulated (from each other) turnouts to create a crossover, can my DCC engine cross over the insulators without stalling?

[Nathan]

Ken,

If you just do what you have shown, yes you will get a short circuit.  What you show happens with a reverse loop.  There are automatic circuits that one can buy that will solve the problem.  They run from $20 to $50. Which one you use will depend on what else you need to do.

The same is true for you crossover.

Nathan

[Jim Banner]

While this problem is most commonly caused by a reverse loop, any track configuration which can lead to a train traveling forward in one direction, then later traveling forward in the other direction, both on the same piece of track, will lead to this same problem.  What is required is a  "reversing section" within the loop or other configuration such that the polarity of the reversing section can be changed as required to match either the polarity of the approach track or the polarity of the departure track.  An autoreverser, as Nathan mentioned, is a device that will automatically change the reverse section's polarity when it detects a short circuit caused by a train entering or leaving the reverse section.  In many cases, you can save the cost of an autoreverser by linking the reverse section to a turnout (track switch).  This can be done by using a switch machine with contacts, or adding an Atlas Snap Relay to an existing dual coil switch machine.  In either case, the contacts can be used to reverse the polarity of the reversing section.

You can see an example of this concept by clicking on the link below:

http://members.shaw.ca/sask.rail/dcc/loop/loop.html

[taz-of-boyds]

If you want to study the topic you can go to:

http://www.wiringfordcc.com/track_2.htm#c4

There is a tremendous amount of material there if you spend some time there. The reverse section can get interesting depending on what you do, and there is an important rule, only one entrance to a reversing section should have a loco (or powered car) crossing it at a time, or you may get a short even with an auto reverser, and trip a circuit breaker.

One interesting reversing section I came up with for one of the guys can be seen here:

http://www.nscale.net/index.php?q=gallery&g2_itemId=54790

It actually has 5 entrances to the reverse section.
Charles