Reverse loop wiring with sub-mini toggle switches

[JHinPA]

Hello, can anyone please explain how to wire a reverse loop. I have a reverse block wiring schematic

but I am still confused. thanks in advance for any help, JOE

[gandydancer19]

You need to use one switch for DCC layout wiring that is called a DPDT switch.  (Double Pole Double Throw)  The switch should be an  ON-NONE-ON type.  That is, no center position.  The diagrams are usually fairly simple.  Try this link for DCC reversing:  http://www.waynes-trains.com/site/dcc/DCC%20Basics%20PT4.pdf

If you are wiring for a DC layout, you also have to use a second reversing switch for the mainline tracks.  That switch is connected to reverse the entire layout except the reversing section.  The DC layout reversing switch wiring is not shown in the above link.

[peahrens]

To me, the big issue is whether you're doing DC or DCC.  If the latter, srrongly suggest putting an auto-reverser circuit board on the reversing loop, the outcome of which is that you don't have to throw any polarity / phase reverse switches manually at trains enter / pass through / exit a reverse loop;  it all happens automatically.

One option is DCC specialities OG-AR, from Tony's Train Exchange.  Call and ask for Tony if you need advise.  I love my DCC system (I have two reverse loops) where I throw turnouts to make the trains go where I desire and the electronics take care of the rest automatically.

http://www.tonystrains.com/products/dccspecialties.htm

[Soo Line fan]

The locomotive(s) enter the loop from either direction, it does not matter which way.

The DPDT switch controls the power polarity to the insulated section shown at the top of the drawing. This switch should be thrown to the same polarity as the power pack prior to the locomotive entering this area.

Once in the insulated section, the throttle is closed. This section should be longer than any combination of locomotives you plan to run.

The direction switch is changed on the power pack. The polarity of the entire layout is now changed.

The  DPDT toggle is also changed.The polarity of the insulated section is changed to match the layout.

Turn the throttle up and proceed through the loop.

[Train Modeler]

Here's a good resource for info:

http://www.nmra.org/beginner/

http://www.nmra.org/beginner/wiring.html

Richard

[gregc]

Soo Line fan

The locomotive(s) enter the loop from either direction, it does not matter which way.

The DPDT switch controls the power polarity to the insulated section shown at the top of the drawing. This switch should be thrown to the same polarity as the power pack prior to the locomotive entering this area.

Once in the insulated section, the throttle is closed. This section should be longer than any combination of locomotives you plan to run.

The direction switch is changed on the power pack. The polarity of the entire layout is now changed.

The  DPDT toggle is also changed.The polarity of the insulated section is changed to match the layout.

Turn the throttle up and proceed through the loop.

This sounds a bit complicated, and I had to re-read some of Linn Westcott's HO Railroad that grows.  Westcott describes wiring a simple reverse loop as Soo Line describes, but later, when describing a more sophisticated control panel, actually uses separate reversing switches for both the mainline and the reverse section.

Using separate reversing switches for both the mainline and reversing section avoids the need to stop the engine and toggle both the power pack and reversing section switches.   Using separate switches also means the power pack switch should be left alone (i.e. not used).

Separate switches independently control the polarity of the mainline and reversing section, in other words, are used to control the direction of the train in each section (not the power pack switch).

Because the engine can enter the reversing section in two ways, the reversing section switch will either match (both up or down) or not-match the mainline switch (opposite one another) depending on which way the reversing section is entered.   The reversing section switch should be set correctly (match or not-match) before entering the reversing section depending on which way the reversing section is being entered.   Once completely in the reversing section and before leaving the reversing section through the other route, the mainline switch is toggled.   And this makes sense since the engine is now moving in the opposite direction on the mainline.

This works for multiple reversing sections and should work for DCC as well, but an auto-reverser would also work.

I think the NMRA Expanded Track Plan Plus page is the 2nd link Train Modeler was trying to post.  It has a section on Wiring a Reversing Situation.

[rrinker]

 For DCC, the single switch will work just fine, as drawn above. It's nicer with an auto-reverser since you don't have to do a thing but make sure the switch is properly lined, but a toggle wires as the diagram previously posted will work just fine. At any time once the train is in the loop section, you can flip the toggle, without stopping the train. The 'polarity' of DCC does not control the direction of the train.

 Another way to accomplish a DCC reverse loop without electronics is to use contacts or a microswitch on the switch motor to operate a DPDT relay to flip the polarity. This way it can always match no matter which way you enter the loop. And there are never shorts, since the polarity will match ahead of the train crossing the gaps. An auto-reverser works by waiting for a short and then swapping the polarity.

             --Randy

 

[BroadwayLion]

LION (of course) has he own way of doing things like this. Him applies power to the main line, and not to the loop. There are four insulated rail joiners just beyond the switch. In the NORMAL position the switch is aligned to enter the loop on the main track, and the loop gets its power from the approach track. the train must stop. Usually this would be a staging loop or something, but even if all you are doing is running around the roundhouse, you still must stop before re-entering the main line.

When you throw the switch to allow the train to leave the loop, the loop is now getting its power from the exit side of the switch. The transition is seamless, and no extra switch is needed. Well that would be the case, anyway, if you were using Tortoise switch machines with their extra contacts. If you are using a manual switch, or a twin-coil switch machine, then you will need an external switch, but once you picture what is really happening, then it becomes easier.

LION has gaps built into the loop so that the train will stop automatically once clear of the fouling point: It will only continue when the exit switch is aligned for the train.

ROAR