Problems with Peco curved turnouts?

[RobertInOntario]

In the past, I've had problems with curved turnouts, even with Peco ones which are supposedly the best quality.

I'm working on a new, small layout and I've re-used one of my older curved Peco turnouts on it. Most of my locos and coaches pass through them OK except for one of my tender-drive British locos & 1-2 of my coaches also derail when they pass through them as well. The frog area seems to be the worst area.

It's possible that this older turnout is damaged so I'm wondering if I should simply replace this turnout by buying a new one. Or, have other folks had trouble with Peco curved turnouts? Maybe I'd be wasting my money and should simply revise the layout plan so it doesn't use any curved turnouts? BTW, this curved turnout is placed on a very flat surface, so I doubt that any unevenness is causing these problems.

Thanks,
Rob