DC - DCC

[iseman60]

Can a Bachmann EZ DCC automatic reversing loop unit #44912 be use with EZ reversing track with standard DC?

[ACY]

No, the automatic reversing modules are only to be used with DCC layouts and are for reversing loops or reversing sections, and not for a point to point layout where you want to run a trolley or train from one end then switch directions on the end.

[richg]

Use a double pole. double throw switch to reverse a DC layout.

http://modeltrains.about.com/od/track/ss/Reverse-Loops_2.htm

Rich

[duff]

Although I would disagree about wiring as shown in that linked drawing.  I think it would be better to feed the mainline through the reversing switch, as it is the mainline that is changing directions.  the train enters the loop, and you then operate the DPDT switch, which would then allow the train to smoothly leave the loop and enter the main.

[richg]

Although I would disagree about wiring as shown in that linked drawing.  I think it would be better to feed the mainline through the reversing switch, as it is the mainline that is changing directions.  the train enters the loop, and you then operate the DPDT switch, which would then allow the train to smoothly leave the loop and enter the main.

Suggestion. Put up a drawing for him in case he is not electrically proficient. That is why I looked in my Links and found the DC reverse loop issue. I have always believed a picture is worth a thousand words.

Rich

[duff]

Let's see if this helps.

If you scroll about half way down this page:
http://www.modeltrainguide.com/index.php?mode=displayarticle&section=5&article=4
you should see a section about Reversing Loops, with a sketch.

The idea is to treat each switch not as Forward/Reverse, but timetable direction, say Eastbound/Westbound.  Switch B for the reversing loop may not be needed if you will only run the trains one way through the loop.  It is the mainline section, controlled by Switch A, that has a change of direction and must be switched.

[jward]

Although I would disagree about wiring as shown in that linked drawing.  I think it would be better to feed the mainline through the reversing switch, as it is the mainline that is changing directions.  the train enters the loop, and you then operate the DPDT switch, which would then allow the train to smoothly leave the loop and enter the main.

you are wrong there. it is the mainline track bus that is connected to the power supply, thus changing the switch changes the direction of the loop track, not the power bus. whether the power bus connects to the center two contacts, and the loop track to the ends of the "x", or vice versa is irrelevant. either way works the same.

a simpler way would be to purchase an atlas  #220 controller and wire it according to the directions that come with it.

both methods can be used with either dc or dcc.

[Doneldon]

iseman-

I don't know if the previous answers addressed your question so I'll give it a try, too.

The EZ DCC Reversing module won't work with a non-DCC set up. It will detect the short when the loco's wheels cross the gap between one polarity and the other, and it will reverse the polarity in the rails, but that will change the loco's direction. The problem is that track polarity controls train direction with DC but the decoder in a loco controls that loco's direction.

I haven't used the Bachmann reversing module which automatically sends a train, generally a streetcar or interurban, back the way it came. However, they have sold it with non-DCC sets so it should work with DC track. What it won't do is work with DCC for the same reason the reverse loop module won't work with DC set ups: The change in track polarity won't reverse a DCC loco because the decoder will maintain train direction regardless of track polarity.
                                                                                                                                -- D

[Jim Banner]

The circuit Rich linked to will work BUT you have to throw BOTH the toggle switch AND the reversing switch on your power pack while the train is in the loop.  Throwing the reversing switch reverses the polarity on the mainline which enables the train to go the other way on the mainline (compared to the direction is was going just before entering the loop.)  Throwing the toggle switch keeps the polarity on the loop the same by reversing the power pack reversal.  When you throw the power pack reversing switch like this, the logical connection between reversing switch and direction is lost.  Most people who use this system stop the train in the loop while throwing the toggle and power pack reversing switch to keep the train from suddenly going into reverse and back into forward if their timing is a little off.  In my opinion, it is a lousy system.

A better system is to have two toggles, one to control loop polarity and the other to control mainline polarity.  These are relative polarities, relative to the power bus.  The polarity of the power bus is controlled by the reversing switch on the power pack and can now be marked as forward and reverse.  The mainline toggle switch can be marked eastbound and westbound (or northbound and southbound) which will be the direction of the train when moving forward.  Remember that a westbound train is still a westbound train even when it is backing up.  The loop toggle or toggles can be marked clockwise and counterclockwise depending on which way you want to be the forward direction around the loop(s).  This is a great system if you are using schematic or map type control panels and is easy for beginners to learn even if they have never run your layout before.  If memory serves, this system was advocated by Lynn Wescott.

If you like walk around control, there is yet a third way of doing the job.  Instead of having only one reversing switch on your walk around throttle, you have two.  One is for the mainline and the other is for all the loops wired together.  Alternately, if using a block system, the block toggles or rotaries have four poles per throttle, two for mainline power and two for loop power.  The reversing switches on the throttle(s) can be marked "east" and "west" as being the direction the train will move on the main and "CW" and "CCW" as the direction the train will move in the loop(s).  I used to build these throttles or "CAB's" in small plastic boxes with just a pot, two SPST toggle or slide switches and a small light bulb.  Each of these connected via 6 wire telephone cable to a its own power control box which contained the power supply, speed control I.C. and reversing relays.  By having the heavy, heat producing components stationary and only the controls for them in the walk around hand held part, the wiring in between was light, flexible and could be as long as you wanted, plus the hand held part stayed cool, even if running multiple large scale locomotives drawing many amps.  These were particularly popular for running garden railroads but worked very well with small scales too.

Going back to the original question, I see no reason why a straight forward loop to loop layout could not be run automatically on dc using a DCC autoreverser.  Unlike with DCC however, you would wire both loops directly to the power bus and connect the mainline to the power bus through an autoreverser.  No special track would be needed.  You would have to go around the loops in the same direction each time unless you added manual direction switches to the loops (this is where the circuit linked to by Rich would be perfect) and you would have to use spring switches (turnouts) or some circuitry to throw the switches automatically.

[jward]

jim,
if you're going to do to all that trouble and expense (auto reverse modules ain't cheap) and still be restricted to only running around the reverse loop one direction, why not use a bridge rectifier in place of the auto reverser? you'll still have the directional restriction, but it will only cost about $5 instead of $50. ac terminals on the rectifier are connected to power supply, dc ro track in reversing section.

[Jim Banner]

jim,
if you're going to do to all that trouble and expense (auto reverse modules ain't cheap) and still be restricted to only running around the reverse loop one direction, why not use a bridge rectifier in place of the auto reverser? you'll still have the directional restriction, but it will only cost about $5 instead of $50. ac terminals on the rectifier are connected to power supply, dc ro track in reversing section.

But then you are still having to throw a switch to reverse the main.  With the reverser, this is done automatically for you.  Good for things like Christmas displays.

Jim