The Doc

Has anyone had a problem with the rear wheels derailing on their model? Mine is okay when running bunker first, but when running forwards the trailing axle (unpowered) derails at several places on my layout. It's not the end of the world because the wheels become re-railed further around the layout, after clattering a bit over some pointwork, and the driving wheels remain on the track, but it does look a bit silly. My track-laying may not be perfect, but other locos manage fine 9 times out of 10. I've checked the back to back measurements and no problems there, but I wonder if the vertical springing on the rear axle is not strong enough. Ironically, I've got the opposite problem with a Hornby A4, where the front bogie spring is so stiff that it lifts the front driving wheels clean off the track.