Hi Benn
I too had problems with my Hunslet, despite cleaning the wheels thoroughly (which did improve things a bit). I'm on straight DC, but the loco would stall on plain track, not what I was expecting for something fitted with a keep alive chip. Anyway, after much head scratching I went to take the keeper plate off to see if there was a pickup issue and found that it had been screwed on extremely tightly. Having found no pickup problems I put the keeper plate back on, but only tightened the screws to the point where they stopped turning. Running was transformed and now at least on a par with my Farish 04.