coolaudio

I recently purchased the 2014 lego cargo train 60052. I had an issue with no power from battery box. I tried 2 different sets of new duracell aaa batteries, still nothing. Went back to toys r us and they happily replaced battery box and included a set of toys r us batteries that worked. On returning home I popped the duracells back in and not working..on closer inspection the duracell batteries positive tips are shorter than regular batteries and aren't making contact...thought I'd mention in case anyone else gets same problem..cheers