I recently purchased a new Proto 2000 PA, which probably had a lot of shelf time. At first, it ran great. Now, after about 15 minutestotal running time, it runs for about 5 feet and then stops. If I give it a little nudge, it runs for another 5 feet and stops, and so on ... . The tracks are clean and other Proto locomotives, and other makes, run fine over the same track using the same power pack set at approximately the same voltage level. Is it possible that it needs a cleaning and/or a lube job, or do I have a bigger problem? Any help/suggestions will be greatly appreciated! Thank you.