I've a mixture of prewar Hornby, including a P.E., B.L. Duchess and Royal Scot. Added a year or so back was Lionel's Kinlet Hall, a Webb 2 2 2 2 and a much modified pair of Lima 4Fs. So with both 2 rail and 3 rail plus a.c. and d.c. to contend with I bought Gargraves track as all rails are insulated from each other. But then I came up with the problem of fine and course scale wheels..... in the end I converted all engines to 3 rail to make things simpler.
The points turned out to be a problem for the fine scale wheels of the 4Fs and the Webb. The Webb's leading and trailing pair are being rewheeled but I found the only problem with the other fine scale wheels of the 4Fs and some of the stock is that the flanges drop down in the frog area leading to occasional derailing. The cure - tighten the check rail gap, and deepen the flanges by gluing a transparent plastic disc to the rear of the wheels. This prevents the wheel dropping in the gap ahead of the frog blade. This seemed to work just as well with Hornby's prewar 3 rail track points so it maybe an easy method of getting old and new to run alongside each other.
It's pity that Lionel are not going to make the Witherslack Hall set announced for later this year. We have driven both Witherslack and Kinlet and it would have been nice to repeat the enjoyment in O gauge, but I suppose we could get their Hogwart and do a spot of repainting....