Electrical short - Realtrax to "0" tinplate

Often a insulator will slip out of the old O gauge track on the center rail, since the ties are metal you get a hard short.

Examine the center rail closely at each tie, look for a bluegrey heavy paper insulator between rail and each tie.

If you can't find anything wrong:

Split the track so power can only go one way from the lockon.

Disconnect midway down the length to the switch, see if the short goes away.

A) If it did the problem is past the disconnected point.

 1) Reconnect, Move down and disconnect farther away. Retest.

 2) If the Short is still gone repeat 1, if not examine track between the 2 points you disconnected.

B) If the short remains, disconnect the track halfway between the old disconnect and power. Test.

 3) If short is gone examine track between the new disconnect and old disconnect. If you can't see it, split the length and reconnect to power.

 4) If short remains, repeat B)

Combining the A and B processes you can eventually narrow it to one section of track, get rid of that piece (It's shorted) and use another one.

Where, exactly, is the sparking?

Is the fahnstock clip on the lock-on solidly riveted to conductor?  A bad connection there would be higher resistance, and heat when current is flowing.

Also check for crude under the lock-on conductor where it attaches to the track.

With DCS there is always voltage on the rails.  Does it heat when no train is running on that section?

  --Joe

Hello Joe,

Yes, it does heat up when the train is running.  I changed contactors and changed a section of the track.  Still get's warm to the touch at the connecting point.  Ran two engines for abouot 15 minutes and got no spark at the connector this time.  Russell, the guy who answered above your reponse has a series of tests that I am trying to comply with and having alittle difficulty understanding....but as long as I don't burn down the house....I'm happy!!!  Thanks for the response and will still keep on figuring this thing out!

Regards,

Larry Williams

Russell,

Thanks for the info.  Trying to understand your instructions.  Moved to a different section of track and replaced one section.  The grey insulation IS in place on all pieces.  Changed the contactor and still get's warm to the touch after running the trains for about 15 minutes.  Sooner or later...I should figure this thing out!  Thanks again.

Regards,

Larry Williams

OK, Not sparking now but contact is warm after running.

2 Possibilities:

1) Running command control at 18VAC or more and the lockon bulb is getting hotter than normal. Many who run command control do not use lighted lockons for this reason, also the bulbs burn out faster at max power.

2) Running several or many lighted passenger cars and or old Motors that draw a lot of current or both. Or running several engines together thus pulling lots of power.

This can cause the connection to get warm, it's not really designed for that amount of power continuously.

In this case, Try using 2 connections spread apart by a few sections to share the load.

Sparking may well have been a poor connection with the old contacts.

IF these are the MTH RealTrax Lockons, Make sure the contacts are clean and not flattened out too much, they should have some bow to them. The point under the track where they contact also should be clean and not popped loose, it's held in place by plastic as I recall. I press those in toward the track a bit as well.

An  AC ammeter would narrow this down as well, Arcing causing heat or just lots of current flowing. Note that most inexpensive ammeters do not measure AC current at up to 10 amps, which our trains can pull. A way around this: Put a low resistance hi wattage shunt in series with the red wire to the track, Measure the voltage dropped across the shunt. Divide volts across shunt by resistance of shunt to get current flow.