The pick up principle is exactly as on the Bachmann split chassis units, and suffers from the same problems, as observed by posters above. As non-conductive muck builds up, pick up falters. Eventually the plating on either or both of the stub axles and axle locations wears through and the pick up becomes worse than ever. Sparing lubrication, and a small addition of powdered graphite will help for a while... The axle muffs and gears also tend to become brittle and apt to split as they age: it is a short life construction, no point hiding from the fact.