I am starting my first DCC layout after being away from the hobby for more than 30 years. I'm planning to put a double slip between an eastbound and a westbound track. How can I wire the area to include auto power reversing modules and to avoid short circuits? I assume I will need insulated rail joiners on all the double slip rails but do I need them anywhere else? How many reversing modules will I need?
I have two types of double-slip switches on my layout, a Fast Tracks handlaid #6 I built myself and two Walthers/Shinohara #6 DCC-friendly. Neither requires elaborate wiring differing from the rails leading into them. If the frog is isolated, and the points move well to lie against either side fully, you should have no problems. I tested mine for the first time a couple of nights ago, no gaps, no reversers, and the locomotive shoving the CMX track cleaning car didn't stall or cause a short.
Can you post a diagram, even a hand drawn one, of your track plan?
Typically when crossing over between two mains, as long as you wire them both the same, there is no reversing situation created and no autoreverse is needed.
If the layout is a dogbone shpae, two mains connected with loops at each end - you isolate those end loops and use an autoreverser on each loop. Then you can have any number of crossovers single or double, between the main lines in the shank portion of the bone with no need for any special consideration.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
If an engine is heading west on the westbound rails and crosses over to the eastbound rails but continues to head west, won't that cause a problem without changing the 'polarity' of the eastbound rails? Or is this merely me thinking like I'm still wiring a DC layout?
Phase conflicts and polarity conflicts work exactly the same way, and for the same reason. So, you only get conflicts when the rails on the other side of whatever are reversed, such as on the other side of an oval. That's when you need a reverser/DPDT at one of the two diagonal-accessing turnouts. But if you have a DS running between two ladder tracks, the ladders are all wired the same, rail closest to the walls red, rails closest to you black..or whatever colours. So, the DS's rails should be wired the same way. You wouldn't place a DS between two ladders and wire the close rails with the opposite polarity/phase as the ladders.
Brooklyn Guy If an engine is heading west on the westbound rails and crosses over to the eastbound rails but continues to head west, won't that cause a problem without changing the 'polarity' of the eastbound rails? Or is this merely me thinking like I'm still wiring a DC layout?
You are thinking DC. DC controls the track, DCC controls the engine. Command a DCC engine to go forward and forward it goes, east west north or south.
That means when you wire a DCC layout, with the east and west lines running right and left, the top track on each line is wired to the same polarity and the bottom tracks are wired to the other polarity.
Henry
COB Potomac & Northern
Shenandoah Valley
Brooklyn Guy If an engine is heading west on the westbound rails and crosses over to the eastbound rails but continues to head west, won't that cause a problem without changing the 'polarity' of the eastbound rails?
If an engine is heading west on the westbound rails and crosses over to the eastbound rails but continues to head west, won't that cause a problem without changing the 'polarity' of the eastbound rails?
In the top portion of the diagram that follows, using a single crossover for simplicity, both mainlines are wired the same way, each rail being represented by a different color (i.e., red and blue). In that case, there is no reverse polarity, no short, no need for an auto-reverser.
In the bottom portion of the diagram that follows, the two mainlines are wired opposite each other since they form a loop at each end of the track plan. In that case, there is a point of opposite polarity where the two mailines meet in the center of the crossover which would cause a short.
The best solution in that case is to wire the the two mainlines the same way as in the top portion of the diagram and isolate the loop at each end to create two reversing sections, each loop controlled by its own auto-reverser.
Rich
Alton Junction
Leave it to Rich to have a ready picture. Yes, set up like the top picture, you can cross back and forth all you want, no shorts. DCC, the polarity on the rails has no effect on the direction a train moves. In fact, that's how DCC autoreversers work - they change the polarity under the moving loco to match the track it is connecting to. With DCC, you tell the decoder to move 'forward' (say, the cab end of an F unit), and it moves with the cab end leading. You can pick up the loco, phycisally turn it end for end, and it will still run in the directuion the cab is facing. You can disconnect the wires feeding the track, and hook them up the opposite way - the loco will still move in the direction the cab is facing.
Technically it's phase, since DCC is a square wave signal, but you can think polarity if that makes it easier.
My whole layout is this way - two loops, one at each end, on different levels, with a double track main line connecting the two with a helix in the middle. Only 2 reversers will be needed - one on each loop at the end of the run. Along the main - as many sidings and crossovers as I want, and none will ever need special wiring or a reverser, because they will all be like the top picture in Rich's post.
rrinker Leave it to Rich to have a ready picture.
Leave it to Rich to have a ready picture.
Thanks, that what I finally understood. It takes a while for things to sink into an old brain that's used to doing things one way for a long time.