Enquiring minds want to know

Actually...I want to know. Not sure if anyone else is interested, but I figure all the mommies that could possibly read this might have an answer for me. WHY does the thomas the train show sing with a brittish/foreign accent, but the trains clearly speak american? My only possible thought on this was that maybe this show was originally made overseas and when it was brought over to the US someone had to translate it americanized...because of slang? Obviously I have no idea, please let me know if you know.