QUOTE I'm sceptical of the idea that decent haulage can only be achieved by fitting traction tyres , since US HO has been a traction-tyre-free zone for several decades , yet US HO locos are certainly expected to haul long trains as a matter of course , and their running has been used as a stick to beat OO for many years I told you recently on another thread this is because US outline is considerably larger and heavier than European including UK outline. This still hasn't changed. In order to get decent traction you need weight or something which will give purchase on the track. If your loco is light the wheels will spin wildly while the train doesn't move. I wont give any specific examples as it may be distressing for some.