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Left rail and right rail are extremely important when wiring your ARSC. There are several ways to keep this straight. If you have used two different colors of wire for your track power bus wires, call one color left and the other right. If you already have your DCC systems, and also have a voltmeter, you can use that to tell left from right. Select address zero, the analog address, and give it full power. This will place DC voltage on the track that you can see with a voltmeter. One rail will be positive, the other negative. If the left rail going into the south portal is negative, all negative rails are left rail.

Regardless of which way you keep track of left and right rail, it's very important to keep that straight - to and including where you connect the power pickup wires (pins 5 and 6) to the track power bus wires.

Looking at the illustration above, notice that pins 1, 4, 5, and 8 are listed as "left" rail. If you're using the color of bus wire to keep track of left and right rail, you might want to substitute "left" for "black", for example. Or, if you're using the DC polarity of the rail as previously discussed, you might want to substitute "left" for "-" (negative). Of course, pins 2, 3, 6, and 7 are right rail, which would then be "white", or "+" (positive), as in our examples.

Here is one very important point: When considering left and right rail for the north portal, it is in relationship to the track entering at the south portal. Don't follow the mainline around to the north portal and match that polarity with left and right rails. Think of it as a reverse section where the polarity is matching the south portal. As such, you will always use the south portal polarity as the reference.

You can actually start wiring anywhere, but I like to start at pin #1 and work up to pin #8. Since the wiring is left - right - right - left - left - right - right - left, it's easy to number the connections right at the rails. Consider the illustration below: ML = Mainline, NP = north portal, and SP = south portal.

Portal Wiring: Since pin #1 is the left rail of the south portal, we start there by numbering that rail #1. Obviously, the other rail is #2. We've now taken care of Left - Right. Next is the north portal, which is Right - Left. Since we finished with right, and the next pin is also right, we just move to the other end of the reverse section on the same rail and number it #3. Obviously, the other rail is #4. That was easy, we're half done.

Track Power to the ARSC: Now we move back to the mainline at the south portal. Since the last rail we labeled was the left rail, we stay on the left rail to number that mainline #5. Obviously, the other mainline rail is #6. This is a very important point. If you just continue up to the mainline at the north portal, and stayed on the same rail, you will be wiring it wrong. It's important that you wire #5 to the track power bus wire that feeds the mainline track going into the south portal left rail. If it's unhandy to wire it right at that point, you can wire it into the track power bus wire anywhere, as long as it's to the same color (polarity) as it is at the south portal left rail.

Reverse Section Wiring: Lastly, we move back to the reverse section itself, staying on the same right rail as #6, and mark it #7. Obviously, the other rail is #8. Our illustration shows a short sub-bus so 7 & 8 can have feeders close to 1 and 2, and another pair close to 3 and 4. Note, for reverse sections only 2-1/2 feet long, or shorter, this is not so important as long as there are no rail joiners within the reverse section.

Final Isolation Test: With the wiring done, before you plug the ARSC into the harness socket, check to see that all the rails are still isolated from each other. This eliminates the possibility that you caused a short in the ARSC harness socket, or anywhere else.

Final Polarity Test with a DC Voltmeter: If you have a DCC system, select address "00" (the analog address) and give it full throttle to place DC power on the rail. If you don't have a DCC system, connect a DC power source to the track power bus.

Use a DC voltmeter to check your work. Check to see which portal is powered. Remember, one will be powered, the other will be in the detection mode (no power).

Let's say that the north portal is powered and that the right rail, as going into the reverse section from the north portal mainline, is positive. NOTE: it's OK if your left rail is positive, it doesn't matter which is positive or negative for this test. If you prefer to make yours like the illustration above, all you have to do is reverse the train's direction (or if using a DC power supply for the test, reverse the power wires to the track).

The north portal and Reverse Section should have the same polarity as the main line. Notice that the south portal doesn't have power. Actually, your meter may show a smidgen of power, that's normal. But it won't have full track power.

If any section of track has the wrong polarity, reverse the wires going to it. NOTE: if the mainline polarities are not opposite each other, as shown in the illustration, you don't have a reverse section and shouldn't be installing the ARSC there.

Now short the gaps between the other portal and the mainline - to make the ARSC switch polarities. Both gaps must be shorted at the same time, as if an all-wheel power pickup loco has just crossed the gaps. You should hear the ARSC click, unless you mounted it in a place that could muffle the sound.

If you heard the click, polarity has changed. If you didn't hear it due to its location, polarity still may have changed. To find out, check that portal's voltage. If it has track voltage, polarity changed and is ready to test. If your reverse section matched the polarity in the last test, it should now match the polarity shown below.

If the polarity of the south portal doesn't match the mainline, reverse the wires going to it. NOTE: since you already checked the reverse section's polarity in the previous test, it should also match. If it doesn't, you have something seriously wrong - check to be sure you really need a reverse section controller in this location.

Final Polarity Test with a Test Bulb: With the analog address "00" selected and given full throttle (or with DC voltage connected to the track power bus wires) and using the illustration below as a guide, connect the test bulb leads at the positions indicated below. The test bulb can be a 14-volt GOW, or any other lower voltage bulb with an appropriate resistor.

If the north portal is powered, the bulb should light with the bulbs leads on 6 and 3, and on 6 and 7.

If it doesn't light at 6 and 3, try 6 and 4. If it lights at 6 and 4, reverse the wires between 3 and 4. If it doesn't light at 6 and 3, or at 6 and 4, something isn't connected properly - check all your wiring.

If it doesn't light at 6 and 7, try 6 and 8. If it lights at 6 and 8, reverse the wires between 7 and 8. If it doesn't light at 6 and 7, or 6 and 8, something isn't connected properly - check all your wiring.

If the south portal is powered, the bulb should light when you place the bulb leads on 5 and 2, and 5 and 7.

If it doesn't light at 5 and 2, try 5 and 1. If it lights at 5 and 1, reverse the wires between 1 and 2. If it doesn't light at 5 and 2, or 5 and 1, something isn't connected properly - check all your wiring.

If it doesn't light at 5 and 7, try 5 and 8. If it lights at 5 and 8, reverse the wires between 7 and 8. If it doesn't light at 5 and 7, or at 5 and 8, something isn't connected properly - check all your wiring.

The Ultimate Polarity Test with a Loco: Use a known good loco that has all-wheel power pickup and a decoder installed (NOTE: Do NOT do this test with an analog loco). This means you must have a DCC system to make this test - the ARSC is NOT designed to work on an analog system, and NO DCC auto-reverse controller will operate properly with an analog loco.

If the north portal is powered, place the loco on the track headed into the reverse section through the north portal. If the south portal is powered, place the loco on the track headed into the reverse section through the south portal.

Select the loco's address and give it throttle to go into the reverse section. If the loco goes through the portal, and gets to the middle of the reverse section without hesitating or shorting the system, you have all the wires connected correctly so far.

If the system shorted out, it's important to know exactly where the loco's wheels were when it shorted out.

If the loco's front wheels just crossed the first set of gaps going into the portal, the portal wires are backward. If the loco wheels just crossed the gaps between the portal and reverse section, the reverse section wires are wrong. In either case, reverse the wires and test it again.

Now run the loco through the other portal. When the front wheels of the loco cross the first set of gaps going into the portal, the ARSC should reverse polarity. If the loco continued on through the portal without problem, wiring is correct. If the system shorted out when polarity reverses, that portal is wired backwards - reverse the wires.

If the loco went into the portal fine, but shorted out when it got to the reverse section, you have a serious problem - check to be sure you really need a reverse section controller in that location.

Note: if a loco won't trigger the ARSC when the leading wheels cross the first gap, check the loco for power pickup. Chances are it needs some service work. When the ARSC is properly wired, the biggest cause of the ARSC not working is locomotive service - something causing power pickup to not be good on one or more wheels. It's a good idea to service your locos on a regular basis, checking for power pickup - not just to keep the ARSC working correctly, but just to have good running locos.