Many thanks. I'm pretty sure it is the track that is short circuiting. Can I just be clear, as I remove a set points to check if they are shorting, do I have replace them temporarily with a piece of straight track to maintain continuity of the circuit? Then if that set of points is not shorting, take out the piece of straight track, replace the points and carry on moving round the circuit as you recommend? Finally, if I find that the cause is a set(s) of dud points, is there any obligation on the seller (Jadlam) to replace them free of charge? Nick