Loop problem

Model Railroader General Discussion (Model Railroader)
1

Hello Hobbyists

I have a new athearn challenger that runs well on my layout. However, it stops cold halfway through the DCC friendly switch after going through a loop. All the gaps are located before entering and leaving the loop.

Thanks in advance for any help.

Doug

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2

A few question need to be addressed:

  • What DCC system?
  • What DCC ‘Auto-Reverser’?
  • What ‘Brand’ of DCC Friendly turnout?

Jim

3

You already know of the electriocal problems gererated by a reversing loop.

So it is a matter of where your gapas are located and how they are switched.

Do other locomotives work correctly through this trackwork?

When you have gaps there may be an issue with a rail joiner not making correct contact, no problem on a loop with no gaps, but when you add gaps you may add dead section if there is an unauthorized or unknoww gap in the system.

Use a test lamp to assure that things are wired correctly. If you can, use and LED, perhaps a bi-color LED, to indicate the status of the tracks.

ROAR

4

ON the Boothbay Railway Village layout, we had a problem with the auto reverser on a reversing loop because the gaps were too close to the turnout. We moved them further away and that cured the problem.

5

A track diagram would make sure we are all on the same page regarding where the gaps are. You can’t attach a photo to your post, you need to follow the instructions for posting photos at the top of the General Foruum.

6

Is this a short or a loss of power to this one engine?

7

hallenger runs through the loop then shorts system at the frog when exiting the loop

Doug

8

Thanks will try moving gaps further back from the switch.

Doug

9

The loop is standard vanilla. gaped at the beginning and end. Challenger shorts out the whole system when exiting the frog.

10

Wiring is correct. I am moving the gaps further back to see if the Athearn Challenger will enter the switch in total.

Thanks

Doug

11

Yep, we need to know this and you should post a track diagram showing the current location of your gaps.

Rich

12

Sounds like a classic reverse loop problem involving faulty wiring and/or misplaced gaps. Can you post a track diagram?

Rich

13

Does this happen regardless of which path, straight or divergent, the engine enters the loop on?

Is this a Peco turnout?

Does the turnout have a powered frog, and if so, how is it powered?

Do other engines pass through just fine?

If you run the engine fast, does it stall, coast through and re-start?

14

That makes three of us. Is the Challenger the only loco that fails to clear the gaps or do other locos cause a short?

Rich

15

Only the challenger.

Thanks for your reply

16

Turn off all the lights and watch the engine closely as it gets to the spot where it shorts. Do you see a spark from the wheels? Where on the track and the engine is the spark?

If it’s a Peco turnout with an unpowered frog, it could be an issue with the wheels “bridging” the gap from one rail to the other at the frog. There is a small plastic gap there, but some engines have wheels wide enough to bridge the gap and cause a short. The simple solution is to paint the gap with a bit of nail polish and make it wider.

This is a big engine with a long wheelbase. If the turnout is too tight, such as an Atlas snap switch, the wheels might not really belong on it at all. Do you have other turnouts of the same brand and size on your layout that the engine works on? Also, the tender is probably involved in power pickup as well, so there are a lot of contact points to worry about when making sure you’re not improperly bridging gaps.

It’s a well-respected maxim in model railroading that the only real way to test your trackwork and wiring is with a big steam engine. You’re learning that the hard way, just like the rest of us did.

17

Thanks for your detailed reply. Since the switch is a Shinohara # 6 DCC friendly I started working on the gaps.

I moved the gaps back to encompass the size of the Loco.

Many thanks Problem solved

Doug Edwards

18

Congrats, Doug. Always rewarding to solve such problems. It is almost always the wiring or the placement of the gaps when it comes to reverse loops. You did good to work through this issue and resolve it.

Rich