The biggest problem was coaches near the front of the train persistently derailing on curves because of the weight of those behind them. Bachmann Mk1s are getting on for 4 times the weight of most wagons.
This is biggest problem I face, previous layout had 24" radius curves and I was lucky to get about 30 Hornby-dublo wagons round until they caved in on themselves, clearly there is some mathematical formula which takes into account factors like weight, resistance, of wagons plus camber, radius of curve etc. Some reason bogie stock such as coaches are more prone to derail.
Clearly pin point axles would help here is the dilemma, most of my pin point axle stock tend to also be very light, hence more likely to cave in on the curves, fact is Hornby Dublo stock stays on the track. What's more you can reverse such stock, try that with tension lock coupling light weight stock.
Still very interesting thread, about time that Australian record was broken, I think it's cheating a bit using 4 locos, I want to see what an off the shelf proprietary single locomotive in either HO or OO can do
As for rubber tyres, that was what was fitted by the manufacturer Triang Hornby some 47 years ago, the 9f evening star was I consider one of the best ever made in terms of pulling power and smooth running. It still has the original tyres on