Having had a bit of trouble with shorting and poor running over pointwork I have gone back to re-checking and re-spacing the wheels on my various models. I'd already done some and I know you should be able to run Hornby RTR on their 14.5mm B2B but I have consistently found that if I re-space them using the spacing gauge to somewhere close to 14.85 give or take a gnat's crotchet, as Humph would say, and shim the check rails on all points with .010" plastikard, everything is massively more reliable - and because the wheel track through the points is predictable you can also work on those tiny deviations from vertical that cause problems with short wheelbase locos.
It's not a five minute job, but I reckon it's worth it. The only problem is that Bachmann is 14.25mm as I measure it, and re-spacing the wheels on the Deltic looks like it might be quite tiresome. The9F is also a bit daunting.