Open-topped carriages are passenger coaches with no roofs.
National Railway Museum Coaches
The National Railway Museum owns two replicas of the Liverpool and Manchester Railway open-topped carriages. Thomas used one of these when he was carrying out demonstrations during his time at the museum. It was painted cream.
Standard Gauge Coaches
The North Western Railway owned one open-topped carriage; it is the oldest coach on the railway, and every year, Edward would take Sir Topham Hatt around the Island on this coach for his birthday. However, the coach went missing one year and was forgotten about. Years later, it was rediscovered on an overgrown siding by Winston and Thomas, and it was taken to the Sodor Steamworks and restored as a birthday surprise for Sir Topham Hatt.
Sir Robert Norramby also owns at least six of the open-topped carriages, which are painted in a similar blue livery. They are used primarily by Stephen and Glynn, who use them to take visitors around the castle grounds. James has also used them to transport the Sodor Brass Band on a few occasions.
Narrow Gauge Coaches
Millie owns three open-topped carriages, which are narrow gauge replicas of the coaches used by Stephen and Glynn.
Aside from the regular coaches, there are also other open-topped carriages that have been seen around Sodor. Ada, Jane and Mabel are open-topped carriages used on the Skarloey Railway, and the Arlesdale Railway also owns their own rake of open-topped carriages.
The open-topped carriages are based on the third class four-wheeled carriages used by the Liverpool and Manchester Railway in the 1830s. Two replicas of these coaches are owned by the National Railway Museum, both of which are used for demonstration runs with Stephenson's Rocket.
In the Railway Series, the National Railway Museum's coaches are painted cream with black wheels and door handles. In the television series, the open-topped carriages are painted sky blue with black lining and gold door handles. Millie's coaches are painted red with the Ulfstead Castle crest on both sides.
- Season 16 - Happy Birthday Sir!
- Season 17 - The Lost Puff, Percy's Lucky Day and The Afternoon Tea Express
- Season 19 - Slow Stephen
- Season 20 - Pouty James, Over the Hill and Cautious Connor
- Season 21 - Runaway Engine
- Season 22 - Forever and Ever, The Water Wheel (stock footage) and Hunt the Truck
- Other - Thomas & Friends in 4-D: Bubbling Boilers
- Throughout King of the Railway and the seventeenth season, the standard gauge open-topped carriages inconsistently change in height.