Bertie is a single decker bus from The Island of Sodor.
Bertie is a small, friendly bus. He can be quite boastful to the engines saying that roads are better than railways, especially to Thomas who he frequently attempts to have races with. He can sometimes be quite grumpy whenever he breaks down or gets stuck, he grumbles about it. But all the same, he does this for fun and he will always be there to help the engines when they are in need.
Bertie is based on an AEC Regal "T Class" London Country Area bus. 8 of these are known to survive in preservation.
Bertie is painted in the common red livery of buses in the United Kingdom, mostly famously used by London Transport.