[meurglysIII]

I have completed and ballasted most of the trackwork on my OO gauge attic layout, and am happy with it. It's Gaugemaster flexible track & PECO points, which most of my stock negotiates with ease. However, my rake of 8 Hornby hoppers is constantly derailing, particularly on curves and points. I'm not sure if it's to do with the flange depth of the Hornby metal wheels, or the back-to-back settings, which I have adjusted to no avail.

Anybody had similar problems or have any insight into the best replacement wheels for general running? - I suspect the wheels not the track are the problem.

Thanks.