Bertie is a red bus who works near Thomas' Branch Line. He is owned by the Sodor Roadway Bus Services.
When Thomas got stuck into a snowdrift, Bertie had came to take his passengers. Later, the two met and they challenged each other to a race to see who is the fastest! Thomas eventually won, and from that day on, the two have been very firm friends indeed.
Bertie still occasionally races with his friend, Thomas.
Bertie is friendly and ready to help anyone in need. However, he can be quite cocky and boastful about himself, especially to Thomas, always joking around and teasing him about their races. He can sometimes be quite grumpy, as whenever he breaks down or gets stuck, he grumbles about it. He is always, however, easy-going and cheerful to everyone he sees.
Bertie is painted in the common red livery of buses in the United Kingdom, mostly famously used by London Transport.
- Season 1 - Geoffrey's Real, Splatter and Dodge (cameo), Edward Tries His Best (does not speak), The Great Western Way (cameo), and Gordon, Spencer and the Flying Scotsman (cameo)
- Season 2 - Unique Engines (cameo), Fire at Ffarquhar, The "Ghost" Warrior (cameo), Jack and the Quack, Sodor Day (cameo), and Ministry (cameo)
- Bertie is the first road vehicle introduced in the series.