Sir Topham Hatt is going to open a new line going to the mountains. A bridge on the line is so high that it reaches the clouds. Henry is afraid of the wind because he thinks it might derail him. Thomas tries to comfort him without success. On the big day Gordon, Henry, and Thomas are ready to make their journey to the mountains with some tourists. When Henry gets to the foot of the mountain, he starts to back down, but Thomas pushes him up the mountain. They get to the side of the mountain and Henry becomes scared again because the line is too steep. Gordon has already gone through the fog and is far away leaving Henry and Thomas. At last they make it to the bridge. Thomas tells Henry that he will go first but suddenly a strong wind blows, and Thomas derails. Soon Gordon returns, he sees Thomas and calls to Henry to help. Soon Thomas hears a buzzing noise. It is Harold, and he helps lift Thomas back onto the rails. Soon Thomas is on the rails again and he calls to Henry that the bridge is safe. Both engines then cross the bridge and make it to the station.
- Annie and Clarabel
- Sir Topham Hatt
- James (does not speak)
- Percy (does not speak)
- Harold (does not speak)
- In one illustration, Henry's face is too big.
- In one illustration, Henry's tender wheels are missing.
- James' splasher is not coloured red.
- Percy's tail lamp is black.
- Thomas' side rods keep changing in colour from grey to black throughout the book.
- Harold's name is missing in one illustration.
- Clarabel seems to be uncoupled from Annie in one illustration.
- Annie is oversized in one illustration, as she looks wider and slightly taller than Thomas, and her body is too low.
- Thomas keeps varying in height and length throughout the book.
- Thomas loses his lamp in one illustration.
- Thomas' yellow lining is sometimes not coloured in.
- The bolts on Thomas' middle wheel rods are sometimes missing.
- Thomas' whistle is too tall and thin in one illustration.
- When Thomas and Henry get to the bridge, Henry's tender is missing.
- In one illustration, Henry's boiler is too short and in the same illustration, Henry is missing his axles.
- Thomas, Henry, and Gordon's wheels seem undersized in some illustrations.
- In one illustration, one of Henry's wheels is missing.