track shorting out in a loop

[treno]

I am trying to achieve a loop and the track keeps shorting out.  I have put a 9" Power Terminal with Insulated Gap track (I have opened the gaps underneath the track) - with and without power to it and when the locomotive goes across the gap track, it still shorts out (either direction). Any help to cure this would be appreciated.

[pdlethbridge]

This picture is from Jim Banners site. Is this what you have?



Go here for more information if it is. http://www.members.shaw.ca/sask.rail/dcc/loop/loop.html

[treno]

Pretty much. I put one piece of insulated gap track per a friends suggestion. This did not work.

[RAM]

What pdlethbridge wrote is what you need.  gaps on both rails at each end, and a dpdt switch. 

[Tylerf]

I dont believe youve told is if you use DC or DCC.

[treno]

DCC.

[Joe Satnik]

4 gaps per reversing loop needed (as shown above).

A DCC reversing module wll do the trick.  It takes the place of the switch shown above.

Trains must be shorter than the track length between gaps.

Hope this helps.

Sincerely,

Joe Satnik

Edit: Added "It takes..." sentence   

[Tylerf]

Actually I'm pretty sure as long as there's no powered units on the back of your train and the cars are insulated the length doesent matter.

[Joe Satnik]

Dear  Tylerf,

You would need plastic wheels.  A metal wheel on the back of too long train can bridge a gap and short out the reverser.

Sincerely,

Joe Satnik

[Tylerf]

Yeah I guess it would, our group seems to be able to do it though but I'm not sure what they do to make it work

[Joe Satnik]

Dear Tyler,

I can think of 3 reasons.

1.) Wheel bounces over high insulating rail connector and never makes contact on both sides of it at once.

2.) Polarity does flip in the turn around loop, but the engine is on solid track power by now, and sees only a momentary slight drop in power.

3.) Polarity does flip under the engine, but the flywheel and caps sustain it's momentum, and the resulting electronic noise is not recognized as a change of command by the decoder.

I wouldn't care to have excessive arcing on my wheels, and extra flip cycles on my reverser, if I could help it.

Another thing.  Look at the Jim's diagram above. 

How much longer than the isolated portion of the loop can you have your train and not have its engine crash into the caboose at the frog? 

1 car length, perhaps?  Why push it?

Hope this helps.

Sincerely,

Joe Satnik   

[hotrainlover]

Tyler,
I just found a similar problem. with one of the insulated gaps, that isolates my programming track from the rest of the layout.  I replaced the insulator.  that solved the problem.  Hope this helps.

[RAM]

Those insulated rail joiners are not really need if your track is down good (does not move).  All you need is a gap.  We did list for years before they came out with plactic rail joiners.  The way I see it they don't look good anyway.