WHITEHORSE, CANADA - SEPTEMBER 28: (NO UK SALES FOR 28 DAYS) Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge view a steam train as they visit Montana mountain Carcross on September 28, 2016 in Whitehorse, Canada. (Photo by Pool/Sam Hussein/WireImage)

WHITEHORSE, CANADA - SEPTEMBER 28:  (NO UK SALES FOR 28 DAYS) Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge view a steam train as they visit Montana mountain Carcross on September 28, 2016 in Whitehorse, Canada.  (Photo by Pool/Sam Hussein/WireImage)