The Misty Island Tunnel is an underground tunnel that runs from the Sodor Search and Rescue Centre on the Island of Sodor until it reaches Misty Island at the other side. The tunnel is used to connect the North Western Railway to the logging railway at Misty Island, and is the most common way of travelling between the two islands.
The Misty Island Tunnel was once used to connect Sodor and Misty Island together, but was soon abandoned and blocked up. Whiff used to take trucks of rubbish down into the tunnel as the tunnel was not in service, and became concerned when the Fat Controller wanted to build his office near the tunnel mouth.
Bash, Dash and Ferdinand knew about the tunnel, but stayed away from it as they deemed it too dangerous to use. However, when he was searching for a way back to Sodor, Thomas decided to use the tunnel despite the Logging Locos' protests, and they travelled down into the tunnel. Unfortunately, the line was blocked, and the Logging Locos ran out of fuel when they used the last of it to help push the rubble out of the way. When parts of the ceiling collapsed and let in light, Thomas used it as an opportunity to send out a smoke signal, and when Percy saw it, both he and Whiff went into the tunnel and rescued them. After the Logging Locos came to Sodor, the tunnel was restored and reopened, and became frequently used by the engines. (TVS; Misty Island Rescue)
The Misty Island Tunnel first appeared in the special, Misty Island Rescue. Since its introduction, it made frequent appearances up until the sixteenth season. Starting with the seventeenth season, the Sudrian side of the tunnel appears to have been boarded up.
- In reality, such a tunnel could not possibly exist, as the smoke and steam from the engines would make the air toxic and suffocate the engines' crew.