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· Registered
153 Posts
Discussion Starter · #1 ·
I just completed a small loop within a loop, alljoints/rail joiners soldered. My problem is as soon as I change the turnout on the far side so the Loco can run into the middle loop I get a short with smoke comming from the joint. Its running clockwise. Heres a rough diagram of the track.


· Registered
3,132 Posts
Yes, you have a short. You have what is called a reverse loop. If you look at the inner loop and start on the outside rail on the turnout on the lower right, if you follow that outside rail it loops around and joins the inside rail at the turnout, a definite short. I would get rid of the reversing loop. If you have to have it then hopefully you have a DCC layout, if its DC you need a few DPDT toggle switches and some rewiring. Are you DC or DCC?

· Premium Member
HO 1950s SP in So. Cal.
2,772 Posts
You have a reverse loop for the inner loop.
It will need a reverse loop controller. An AR-1 similar to this,
If you are running DCC, if DC as the faster typing Lemonhawk says a bunch of switches.

Might be just well off getting rid of the loop.With only one reverse loop you have
no way to reverse again and get going the original way.


· Registered
4,201 Posts
if you are running a transformer for a test, then a DPDT switch will work [DC], you can't run an autoreverser with DC, only DCC ..
You need to put in FOUR insulating joiners, best place would be the exits of the turnout on the reversing section, most common practice .. just to the left of where it says R/H Hornby

· Registered
10,399 Posts
Azatrax has reverse loop controllers for both DCC and

Here is what you need to do if you continue to use
your reverse loop:

1. Place insulated joiners between the turnout and the
track that is the inner loop. You also must
have insulated joiners at the other end of the loop
where it joins the turnout. This creates an 'isolated
section of track.

2. The 'isolated section' will be powered by the Azatrax.
The input of the Azatrax receives power from your
Power pack track terminals if DC. If DCC, it is powered
by your track power.

When you do as above, the 'short' you get at the upper left
turnout will go away. The above solves the 'short' at the
lower right.

Here is how a 'reverse loop' controller works. When the
loco front wheels span the insulated joiners there is a
short. The Azatrax instantly reverses the polarity of
the isolated section and the train continues without
pause. When it reaches the exit end of the section,
the wheels again short and again the Azatrax reverses the
isolated section power and the train continues on. It's
fully automatic.


While Azatrax makes controllers for either DC or DCC,
there are several other makes of controller for DCC
layouts that may be of less cost.


Any time your layout can have a train turn around and
go the opposite direction on the same track, as is your
situation with the inner loop, you have a 'reverse loop'

· Registered
153 Posts
Discussion Starter · #9 ·
I think it's pointless to even have the reverse loop. Once you have gone around it one time you can't get back to it without backing the train into it.

I don't understand why you have this.
Because I don't really kmow what I'm doing LOL. I may ditch the Hornby turn out and figure out a different inside configuration................any suggestions (polite ones please)? I have a Pro Cab to run the finished layout if and when I finish it.
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