Problems with Peco curved turnouts?

[RobertInOntario]

Since it is only a few pieces of equipment that have problems, check the gauge on those wheelsets. Even wheels slightly too tight will cause problems. Are these engines/coaches only derailing when traveling through one leg, or through both legs of the turnout? If they are only derailing through the tighter radius, maybe that radius is too tight for those pieces of rolling stock.

Thanks for these responses. Yes, it's only the tighter (or inner_ curve that's the problem. Also, the tender-drive loco only derails when traveling in one direction through the tighter curve -- when it passes through the curve coming from the other direction, it's fine!

The coaches (that I mentioned) have had 1-2 problems elsewhere on the track so I do think there could be gauge problems with some of their wheel sets. But the loco is usually a good runner so I'm not convinced (yet) if it has a gauge problem. BTW, it's the tender that is the worst offender.

Thanks, Rob