Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Runaway Train?

1848 views
6 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    August 2007
  • From: Lake Havasu City, Arizona, now in Guthrie, Oklahoma
  • 665 posts
Runaway Train?
Posted by luvadj on Tuesday, October 13, 2009 5:40 PM

 This has me wondering.....My Atlas H44-15 with a DCS decoder runs fine, but every once in a while, it goes half way around the layout before it knows that I turned the throttle down or off. I'm using an Atlasmaster DCC setup and it works fine.

The layout only has 2 feeders as it's a 3 X 5 and I gleamed the rails being that the layout is outside. I wipe the rails before every run and check all loco wheels for buildup and keep them pretty clean....

Any ideas or things I could look for?

Bob Berger, C.O.O. N-ovation & Northwestern R.R.        My patio layout....SEE IT HERE

There's no place like ~/ ;)

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,330 posts
Posted by selector on Tuesday, October 13, 2009 5:56 PM

DCS decoder?  As in, you removed what was in there, or you purchased an MTH decoder and installed it?  I don't believe MTH sells decoders, so I am sure you have made a typo...?

In any event, sometimes, whatever the reason, when I start up my Digitrax Super Empire Builder, one engine will being to creep around the track.  I find the throttle, of which I have two, with that engine active, and always find a speed step of "1" on it for some reason.  I zero it and all is well.

The other thing to do is to disable DC operations on your decoder by entering a value of "34" in CV29.  Some people have reported runaway trains upon startup, except that they quickly accelerate to dangerous speeds and often crash before the operator can get the system to do a full stop on emergency.

-Crandell

 

  • Member since
    January 2001
  • From: SE Minnesota
  • 6,847 posts
Posted by jrbernier on Tuesday, October 13, 2009 5:56 PM

Bob,

  I doubt that your engine has a DCS decoder(MTH).  Usually DCC 'runaway' issues are to to electrical issues.  In your case, does it eventually slow down and stop?  With poor electrical pickup(or 'noise' on the track) the decoder can get confused.  It cannot figure out iff it has a DCC signal or a DC voltage - it just keeps going.  Setting CV29 to turn off DC capability will help.  I am not sure what programming capability is available in the Atlas Commander, but I have set our club Digitrax system to not allow DC operation, and we strongly suggest that everyone sets CV29 to disable DC operation.

Jim

Modeling BNSF  and Milwaukee Road in SW Wisconsin

  • Member since
    August 2007
  • From: Lake Havasu City, Arizona, now in Guthrie, Oklahoma
  • 665 posts
Posted by luvadj on Tuesday, October 13, 2009 6:02 PM

 Crandell, Jim, I goofed...that was a typo. I meant TCS decoder, as in Train Control Systems decoder. It works fine otherwise and like I said, it's not an everytime thing.

Yes Jim, it does slow down after a half lap around the layout. I can program the decoder on my programming track, so I'll give CV29 a look at...

Bob Berger, C.O.O. N-ovation & Northwestern R.R.        My patio layout....SEE IT HERE

There's no place like ~/ ;)

  • Member since
    July 2006
  • From: Vail, AZ
  • 1,943 posts
Posted by Vail and Southwestern RR on Tuesday, October 13, 2009 6:18 PM

Another set of feeders might not hurt.  The symptom suggests getting power, but not cleanly enough to decode the signal consistently.

Jeff But it's a dry heat!

  • Member since
    May 2008
  • 4,612 posts
Posted by Hamltnblue on Tuesday, October 13, 2009 7:28 PM

It a common problem that is usually fixed by turning the DC mode off in your engine decoder.  Usually the train will run max speed with no control when the issue shows it's head.

Springfield PA

  • Member since
    July 2006
  • 3,312 posts
Posted by locoi1sa on Tuesday, October 13, 2009 8:14 PM

 Even though you clean the track before every run there are still joiners that can lose contact. The track being outside there is expansion and contraction that weaken joiners. The only option for an outside track is to solder a feeder to every rail. My portable modules go through extremes also. Right from the start they are fed to every rail for reliable running.

       Pete

 I pray every day I break even, Cause I can really use the money!

 I started with nothing and still have most of it left!

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!