Purchased Jingle Bells Express on 12/24/2015, worked/ran fine (maybe 3 to 5 hrs) until yesterday. Turned it on and the train automatically ran at the highest speed no matter if we set the controller at low or medium. There was only one speed, fast, no matter where the controller was set at. Also, noticed that when it was shut off, and we switched the direction switch, the train learched/moved on its own about 1/32 to 1/16 of an inch, without being turned on. Is this normal? What would cause these two issues? Do I need to send the controller unit in for repair/replacement or do I need to return the entire set?