HO Scale loop problem

[treno]

I am a total rookie.  I have set up my HO layout and have made an inside  loop that shorts out.  I was told to pick up some auto reversing track to cure the problem.  This has done nothing.  How do you cure this??? Signed, Treno

[Paul M.]

Is it a reverse loop (loop that causes the train to switch direction)? If so, you'll have to do some complex wiring to change that.

Can you show us the track plan of your layout?

[SteamGene]

Is this DC or DCC?  In any event you need to isolate the reverse loop if such be the case.
Gene

[treno]

It's DCC.

[Paul M.]

Any word on the reverse loop?

[taz-of-boyds]

Treno,

Not having seen a diagram of your track makes it hard to work with directly.  But if you spend some time here:

http://www.wiringfordcc.com/track_2.htm#c4

You should find this material very useful.  Allan Gartner has a tremendous amount of material well documented for DCC.  Please let us know how it turns out!

Charles

[grumpy]

Treno
If you are using a reverse loop purchase a Digitrax AR1  . It doesn't matter if it is DC or DCC it will work in both cases . From EXperience.
Don

[pdlethbridge]

According to digitrax, it's DCC only. Here's why according to them.
It is a common misconception that the AR1 will work with an analog controlled ("DC") locomotive; it will not. The AR1 is meant to be used only in a DCC environment. This is because the AR1 coordinates the electrical phase of the reversing segment with that of the mainline segment. Because DCC is a square wave AC power, track polarity is not an issue as it is with DC powered railroads.
Well. Who's right?

[grumpy]

There was no direction in the package when I purchased it and so I tried it and it seemed to work . I now have it installed on my DCC section and it is great .
Don

[pdlethbridge]

Their site was not very specific about it until I found the above.

[grumpy]

I was running a DCC loco on the DC circuit. That may make a difference ?
Don

[Joe Satnik]

Dear All,

An educated guess if you'll bear with me....

Yes, a DCC reversing module may work with DC but only under these four (4) specific conditions:

1.) The main line is the "block" or "power district" that is "reversed" or "flopped" by the output of the reverse module.  The DC power pack directly feeds the reverse loop track and the input of the reverse module. 

2.) A DC train approaching the reverse loop turnout must take only one direction: the direction that causes the rails to match the loop's (unchanging) polarity, that of the power pack. 

(I will leave it as a mental exercise to figure out what would happen if the wrong turnout direction were taken.)

Taking the correct turnout direction, the train crosses over the first pair of insulating rail joiners (without event) and proceeds around the loop.

When the front wheels cross over the second pair of insulating rail joiners, they short to the mismatched polarity of the main line power district, causing the reverse module to "flop" and switch the mainline to the other polarity.

3.) The speed of the train (voltage of the power pack) must be high enough to allow the reverse module electronics to operate properly.

4.) The short curcuit "impulse" (=extremely small time) current of the power pack (probably related to the speed of the train) must be high enough to be detected as a short by the reverse module, allowing its output to flop to the other polarity.

You may wake up now. 

Hope this helps.

Sincerely,

Joe Satnik       

[Atlantic Central]

Good explaination Joe, and all those "musts" are good reasons NOT to use an auto reverser with DC.

There are lots of better ways to handle reverse loops on DC powered layouts - wiring books for model trains are full of the various choices.

Sheldon

[treno]

Sorry for the delay in responding. Out of town.  I have pretty much have a loop back on to itself.  I was told to pick up Backmann Auto Reversing Track, to no avail. Should I get a insulated gap track instead or will this even help? Treno

[pdlethbridge]

If you are running DCC an auto reverser will help. If your running regular DC or analog, you need a DPDT switch to reverse the current to the section before the reverse loop which may be the rest of the layout, depending on the track arrangement. Not a problem with the right equipment