Hi Bart,

I think you make it a bit too complicated. In my opinion the more axles you got (to a certain number of course) the more power the engine can put on the tracks.

Myself I drive the 6 axle Class 66 and the 4 axle BR 189. The first got 3,300 bhp, the last 6,000 bhp using 1,500 volt dc, 6,500 bhp at 3,000 volt dc and 9,000 bhp at 9,000 bhp.

Although more powerfull, obviously, the Br 189 slips very easily, even when dry. The Class however, never slips even when pulling throttle and even when standing on a slope.

Florijn