I have a Kato SD-40, and on certain spots of my layout, not matter on many times I clean the track and the wheels of the engine, it just stops if the voltage (i.e. speed) of the loco is low enough.
I have a DC power pack (not DCC).
I have narrowed it down to at those spots, the wheels engines, for whatever reason, don’t make contact with the nickel-silver track (i.e there are lowpoints there). How do I bring up the track so it makes contact with the wheels of my engine? I only need to bring it up something like 1/2 a mm or so (I think).
Coincidentally, my Proto N GP-60 works just fine around the track.
This is on a 2.5 ft. x 4 ft. layout that can be transported, but has not been transported (or used) in about six months. I ran the trains and cleaned them, and expected some choppy performance, but I did not expect this. Should I try to use some needle-nose pliers and gently pull up on the track, being careful not to pull the track up from the ballast?
you can shim the low spots with very thin pieces of plastic/paper [.01-.06"] between the ties and roadbed a level and smooth sub-roadbed is essential to smooth operating track. Always take time to make sure my roadbed is smooth and without humps/dips for faultless track. this eliminates headscratching and other stupid human tricks i’ve performed in the past to get my equipment to run right. lesson learned: i’m obsessive about subroadbed/track/rail and has nearly eliminated any operating issues with equipment.
This sounds like a case of poor electrical wiring combined with loose rail joints. You may need to solder your rail joints and provide more power feed wires to the track.
Thanks for the reply. I already have two feeders on that loop of track, in fact, I have a feeder about 0.25 inches from where the engine stops. Hmmmmmm.
I use 3 fairly easy checks to make sure the trackwork is flawless (or as good as my 50+yoa hands can do). All of these came from Model Railroader or here in the forums.
get my eyeball down at rail level. Sight along the rail. I can pick up very slight jogs, misalignments, and kinks in the rails that I could never see looking from above. Fix the track until I can’t find even the slightest horizontal deviation from a smooth curve or line.
get a ruler or straightedge and place it on the railhead. Putting a light behind the straightedge makes this work much better. Again, get the eye low and look for any light between the straightedge and the rail. That’s where your vertical dips are. Move a fairly short (6"?) straightedge along the rail and try to rock it. If it rocks, that’s a high spot. Fix the dips and high spots until they are undetectable.
Try turning the lights down low or off. Then, run the engine at low speed thru the spot that is giving you trouble. I turned my lights off and stared at the trouble spot. You will be able to see the arc quite easily. Bob Whitten
Ughhhhhhhhhhh. Well, I had to do a bit of surgery this past weekend. I tried to level the track, which was already glued to the roadbed, ballasted, and weathered. I tried to take some pliers and gently pull up on part of the track that dipped a little below the adjacent rail. This was causing my Atlas SD-35 to derail (but not the Kato SD-40, weirdly enough).
So I had to replace a section of 9" N scale track and a standard left-hand turnout. THAT was fun work. The SD-35 does not derail any more (at that spot), neither do the GP-60 and GP-38-2 I have. I ran the trains for about 45 minutes yesterday and no derailments anywhere on the layout (2.5’ x 4’).
I’m still having problems with the Kato intermitten stopping though at the same three spots on the layout. My short-term fix is to not use than engine for now.
I had determined that since the SD-40 is the longest engine I have, the trucks don’t flex enough to pick up the minute deflections in the track, which is why it is stopping, because it is not picking up electricity. I will have to try to level the track somehow, hopefully this time without pulling the metal rails up!
I was running a consisted pair of Proto GP-9s (HO) when I noticed a similar problem. The lead engine was cutting out, and then restarting as the consist got a bit further down the track. I hadn’t seen this behavior before, and pretty much everything is rock-solid on my trackwork. Next, I noticed that the engine cut out every time it entered a right turn.
I opened up the shell and found both wires from the decoder to the trucks on one side were disconnected. These are small wires soldered to connectors on the tops of the trucks, and they flex as the trucks rotate. I’d recently done some decoder work on that engine, and I probably weakened the solder joints while doing that. A few quick applications of the soldering iron fixed the problem.
You may have a similar problem inside your engine, perhaps on one truck only. Most of the time, power is still getting there from the other truck, but there are always dead spots on frogs, etc., so reduced pickup can cause problems like this.
The problem areas are not where the switches or frogs are. They are around a 9" radius curve. Maybe I’ll take apart the shell to see if any wires are disconnected. Thanks for the tip.
I had the same problem with a Kato HO scale SD-40 – the electrical pickup from the trucks was through a bronze strip that ran the length of the locomotive on each side, and small protrusions on the trucks to transfer power to the strip.
This was a very poor arrangement electrically because flexing of the trucks would cause the truck to lose contact with the strip, and the locomotive would stall. I think Kato used this arrangement only on the SD-40 before realizing it didn’t work.
The cure I found was to solder wire between the trucks and circuit board instead of relying on the strip.
Before you start taking things apart, what is the minimum radius the manufacturer lists for this engine? 9 inch radius sounds pretty sharp for a 6 axle locomotive, even in N scale. I won’t even ask what the overhang looks like on curves. Also, you may want to make sure the body of the loco isn’t catching or riding up on some part of the surrounding terrain.