I recently acquired "Great Central" from a very reputable dealer. The model had been fitted with a new motor following the problems that they had with the early batch and runns very smoothly. The problem is that it will only just draw 6 coaches up a very slight gradient. I then have to give it a helping hand. The model is heavy. The problem seems to be that the pony truck under the cab prevents the full weight of the loco bearing on the drivers. Is that a correct diagnosis and can anything be done.