Carvalho travelled by train from Baltimore to Kansas City in 1853 at the start of the expedition. The film showed a train on a heritage railway in England hauled by Great Western Railway, later British Railways, locomotive no. 4666 which was built in 1943. The coaches of the train are British Railways mark 1 coaches, built in the 1950s.
Surely the film producers could have found a preserved 19th century American 4-4-0 with period coaches.