i run n scale trains on a layout i built years ago. it was not in use for three years but then i cleaned the tracks and started using it again. it worked fine then all of a sudden the trains only run on one 15" section of track, nowhere else. if i put the train on this spot, give it power, it goes and abruptly stops. i have made no changes to the wiring or the layout. i can test the trains on another layout and they run fine with the same transformer.
how do i diagnose this problem to find the cause? is a 12 v auto battery tester accurate enough to test for voltage or is there something else i can use? this is extremely frustrating as one can just imagine.
is there such a thing as the surface of the rails wearing so they do not conduct power?
I’ll make a couple of guesses here, and you can fill in the blanks if I am wrong. I am going to guess that the power is only connected to the layout at one place, and that the trains operate near that place. So, the first place to check is at the joints between that area and the rest of the layout. Your 12V tester might be sufficient to do the trick, although it is possible that there is enough af a connection that the tester will sense the voltage, but that as soon as there is a load (your engine) the voltage drops. A cheap multimeter would be a handy tool to have here.
No, the surface of the rail isn’t going to wear to where it won’t conduct, but if this is old brass rail it can oxidize, and not condict very well. But, assuming you cleaned all the track the same that doesn’t sound like the problem.
Give a bit more info on where the power is connected, and how the layout is wired, and we’ll get to the bottom of this.
A Voltmeter is what you need to check for the presence of electricity on the rail. Loose or corroded rail joiners are probably what are causing your loss of power.
You should be able to pick up a digital Volt-Ohm-Milliammeter (VOM) from Wal-mart, Home Depot, Lowe’s, Harbor Freight, or similar store for around $10.
An automotive battery tester should work if you turn your power pack up to full throttle as you perform the testing, but if you have what I think you do the large alligator clips on it are going to be difficult to maneuver.
A digital voltmeter will not draw sufficient current to identify a high resistance connection to a section of track. The older analog meters worked better but …
The easiest solution is an automotive tail light bulb with two wires soldered to it (or in a socket with wires). It’s called a test light and is one of the oldest tricks in the book. (Audels book from the 1890s to be specific )
It will draw up to two amps and any bad connection will be extremely easy to find. It’s inexpensive too.
Make a test cord. Attach two wires to your power supply just as if you were going to run them to the track to supply power. But instead of permanently connecting them to the track, attach an alligator clip to the ends of each wire.
Then clip those alligators to your rails at various points around your layout (keep both clips within a railroad tie or two from each other,one on each rail). That will supply voltage to sections of track at a time so you can try your train on that section. If it runs (with the text cord, but not without it) then you know that you are not getting electrical voltage to that section of track and you will need to look for poor connections at rail joints or add supply feeders.
Just be sure that when you clip your test leads to the rails, that you don’t hook them up with the wrong polarity and short everything out. Also watch out that you are working within a block and not compromising the block.
This would be a much more quick and easy way to find out if you have voltage supply problems to different areas of your track.
Yes a meter will give you the most accurate information, but a quick temporary connection of power will help you quickly isolate the areas that are the real problems.
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