Hi all,
  I'm asking this question for my grandson who just got his first train set.  The problem we are having is the electrical pickup that is on the front pilot.  Going around a curve, the headlight stays pretty constant and the locomotive has no real issues.  But as soon as it gets to a straight section of track the headlight flickers a lot, and the engine even stops at times.
  I see that a copper strip that is used to retain the wheel axle on the pilot for each side is the pickup.  I believe that the axle has too much movement on a straight away and therefore causes breaks in the circuit.  Does anyone out there have any suggestions on how to cure this?  Thanks in advance for your help.