Help Needed Diagnosing Power Problem

[Anonymous]

I am having a problem with the locomotive slowing through one quadrant of what can be considered a basic oval on a 4' x 8' sheet of plywood. The track is Lionel O gage not O-27 and I am using two lockon's. With the train traveling forward in a clockwise direction it will slow dramatically in what could be thought of as the upper left quadrant. It returns to normal when it leaves that quadrant. Again it is the upper left quadrant. The louckon's are located in the upper right quadrant and the lower left quadrant.

I have felt the track joints for a hot spot after opperating the train but have felt none. I have checked the voltage rail to rail at various spots around the layout -- prior to , in and across the slow down quadrant. No voltage drops were noted. My meter does not measure AC amps.

Testing the track with rolling stock by hand does not reveal any tight spots.

I have operated the locomotive using each lockon alone and in combination with the same results.

Here is the kicker with the train traveling forward in a clockwise direction the upper left quadrant is the slow down quadrant. Put the locomotive in revese so it is backing around the layout in a counterclockwise direction and the slowdown quadrant becomes the lower right quadrant.

Any ideas or advice?

Thanks much,
Steve

[Anonymous]

Try putting a lock-on in each quadrant.

Tony

[SPFan]

When you did a voltage measurement was the train running? It should be to get an accurate idea of where the problem is. Your voltmeter has a high input impedance. A resistance of say 10 ohms at a a track joint would look like almost zero to the voltmeter ( in other words it would read full track voltage). By running the engine which has a resistance of say 2-4 ohms the 10 ohm track resistance becomes significant. Over half of the applied voltage could be lost at the bad spot in the track. Your 16 volt transformer voltage would read 4-5 volts at the bad spot. The easiest way to do this is to attach another lockon connected only to the voltmeter.
Pete

[lionelsoni]

A tilted board ("upper right" quadrant high, "lower left" low) would have an effect somewhat like what you describe; but I think you would have noticed if that were the case.

[tmackinator]

I have soldered all my track joints and solder wires directly to the track. Forget the lockons. Try adding feeders around the layout, you may need several. I had a slow spot on the layout for about 1/4 of the loop that was caused by one poor center rail connection. Soldering that solved the problem dramaticly. Hope this helps- T.M.