 DATE: The locomotive overtaken by Chitty Chitty Bang Bang in the  main song sequence is a J94 "Austerity" Saddle Tank locomotive. It  has the legend "GWR" (Great Western Railway) on the side. The J94  type of engine was not built until WW2, well after the period the  film is set, and no J94s were ever operated by the Great Western  Railway. Also, the GWR livery was a deep green, not blue as shown.