Reversing loops and DCC

[trailrider]

I haven't thought of this before as I have been running mostly DC locos on my layout, and even then haven't used the reversing loops much. I have DPDT toggles wired in to the adjacent sections where reversing loops occur, so no problem there.

But before I burn up a DCC w/sound loco, what happens when one crosses the boundaries of reversing loops? Since there is basically AC current on the track, and the decoders are activated by pulse width modulation, does anything have to be done when crossing the boundary? Will the DPDT switches have any effect when thrown? Is a special reversing module required? I am using an MRC Tech 6 6.0 for power and control.

 

[ianacole]

When running DCC, you need a DCC auto-reverser...comparison chart here:


http://www.amhobby.com/products/tech/generic/guide_areversers.html

 

[trailrider]

When running DCC, you need a DCC auto-reverser...comparison chart here:


http://www.amhobby.com/products/tech/generic/guide_areversers.html

Hmm! This could get complicated as I have several effectively reversing loops as a result of a spagetti-bowl track plan. Trying to figure which sections actually constitute reversing loops could get complicated. Probably the safest thing is to NOT run my DCC locos through the reversing sections.

With the sound modules, which auto-reversers would you recommend, presuming I can figure out which sections are the loops?

 

[cuyama]

Hmm! This could get complicated as I have several effectively reversing loops as a result of a spagetti-bowl track plan. Trying to figure which sections actually constitute reversing loops could get complicated.

The reversing loops in DC should be exactly the same in DCC. If you know where they are now with DC, they will be in the same spots with DCC.

 

[trailrider]

Hmmm!? Well, I tried one of my DCC/sound equipped locomotives running across a crossover, which essentially creates a reversing loop on my folded dogbone layout. The thing is, I have the layout broken up into a whole bunch of individual blocks, each of which is equipped with a DPDT switch to reverse the polarity when the layout is on DC. Flipped the toggle for the "receiving block" to "reverse", then energized the power in DCC. Crossed over to the other side of the dogbone with NO problem. Obviously, with the loco running in "forward" on DCC, I'd have to throw the DPDT toggles on the remaining blocks...I think. But at least this short test (no pun intended), didn't result in any short circuits, etc. Where I would probably need to run a loco across a reversing loop is when running a switch engine around one of the yards to get to the other end of an incoming train. Since all of my switchers are DC, I'd probably just run that for switching, keeping DCC for "thru" trains, way freights, etc., that run on the continuous portion of the layout.

Thanks for the information on the auto-reversing equipment, however. May come in handy later.

 

[cv_acr]

trailrider: There is really NO DIFFERENCE in reversing loops in DCC vs. analog DC. None. Either way the reversing section must be properly isolated and handled.

The DCC system will automatically shut itself down to protect itself when a short happens.

One advantage with DCC is that you can use an electronic auto-reversing circuit instead of the manual DPDT switch.

 

[trailrider]

trailrider: There is really NO DIFFERENCE in reversing loops in DCC vs. analog DC. None. Either way the reversing section must be properly isolated and handled.

The DCC system will automatically shut itself down to protect itself when a short happens.

One advantage with DCC is that you can use an electronic auto-reversing circuit instead of the manual DPDT switch.

Thanks for that tip. I pretty well came to the same conclusion this morning, running a quick test by throwing the DPDT toggle to match "polarities", which I would do with DC. Since I have the layout wired for DC with the toggles, and am used to doing it that way, I'll probably stick with the toggles, as I have about four or five places that effectively become reversing loops, depending on which way the turnouts are routed. As I mentioned, I probably will mostly use DC switch engines for most of this activity, as opposed to running the DCC/sound locos with the express trains or "time" freights on the main.

Thanks for your help.