Hi i have checked all the above and all seems correct. i am now running the loco without the tender and it still stops as the wheels hit the frog , I am using live frogs. so I assume that it must be the loco wheels that are causing the stalling . The Elite is not shorting or loosing the data from the decoder which was the problem when the tender was attached. the wheels are all perfectly in line and I can't see how they could be adjusted as they appear fixed to the spindle. the brushes are all in place and touching the wheels. This Mallard stops on every point not just one , my other simila locos cross at low speed with out an issue , including the Hogwarts train and Maude 673 and Bach**n locos I have fitted insulated rail joiner in the V of the frog. The only other loco which stops at low speed in a small 040 southern 63 which has never been a good runner, I am reluctant to purchase other locos until this issue is solved many thanks Andy