I have a couple of cars that you have to pay particular attention to when running on a layout. When you place either one on the track for running, they will derail at the same places on the main line. If I turn the car around, it runs just fine.
I examined the cars and everything seems to be fine; wheels in gage, etc.
I know that I am not the only one who has a few “select” cars. I just don’t get it.
Take care,
Remove the trucks and take a look at the bearing where they attach. If one side is worn or cracked, that may be your answer. Check that the trucks can swing freely in both directions and not hit anything like coupler boxes or or other under-car parts.
If nothing else, it may be the trucks themselves. I’ve had to replace a couple of old ones, but since I did that, the cars have all run fine.
I don’t know if this would cause it - but on the subject of trucks - could one of the axles be binding up and then climbing the rails as you enter the turn?
Make sure the trucks are square, meaning all 4 wheels are on the rail with no weight on them. Also make sure the bolster screw is threaded straight into the frame.
Jim
The fact that deraiments occur at the same spot with two cars, is a good sign. What is happening is the wheels are not following the track. NOW the question is why?
1.WHEELS in gauge? - Check track,
2.TRACK & WHEELS in gauge? - check TRUCKS for horizontal & vertical ‘freedom’.
3.WHEELS turn properly? Not rubbing on anything? Check gauge for all 360o?
4.COUPLERS inhibiting movement? Decoupled cars have same problems? - Talgo / Body mount mix?
5.TURNOUTS CAUSE DERAILMENTS more than track. Are wheels coming off at turouts, and then derailing further away (happens)?
ANY or ALL the above can cause your problem. CORRECTION is a process of elimination. I have listed 1-5 in order of probability. EYEBALLS are your first tool. USE them.
Wheel guage is a first and necessary, not to mention easy, first check. You have done that, so in-line tracking might be worth a look to see that the flanges are aligned in the same truck. Even though a gauge might say the at the spacing between flanges is good, the way they track ahead/behind one another through a section of track could be an issue.
Finally, in the realm of likely problems, is the pivoting and anchoring of the trucks, which include swiping against underbody elements, coupler box, flashing, and whatnot. I have found that my MDC Harriman pax cars are prone to truck swiveling problems.
All good suggestions.
I would add one more thing to try. I’ve always found that using the three-point suspension trick to be useful. You leave one truck a bit floppy when tightening the bolster screw and tighten the other one enough so that it has to swivel, instead of being free to rock a little like the other, looser truck. This will frequently solve the kind of problem you’re talking about, as it often is enough to solve such issues as the others have mentioned, especially if they are slight and hard to detect by sight alone.
[#ditto] One thing to add to Don’s excellent list - check the track - is there a joint in the vicinity? is there a piece of ballast or track nail there? Good luck[:)]
Is this on a curve or a straight section of track ?