According to the Mirror, while William took a helicopter to the Commonwealth Games, Catherine took the train.
Not sure I believe the "chance" meeting Catherine had with a journalist's son on the train, outlined in this article. But it does prove that all those comments saying it would be too risky for the Royals to take public transport and they HAD to travel by helicopter, were simply wrong.
It is good to see Catherine travelling by train rather than helicopter.
www.mirror.co.uk/news/royals/kate-middleton-surprises-dad-entertaining-27650025