The Mainline

The North Western Main Line travels from Barrow westward to Tidmouth through southern Sodor. It is approximately 80 miles long.

Route
The main line starts from vicarstown, which meets Sodor with the Mainland. the line starts at Vicarstown before passing through Henry's Tunnel. After this, the line crosses a river, and after that, it stops at Crovan's Gate, home to the Skarloey Railway. After stopping here, the line travels to Kellsthorpe Road, junction to the Kirk Ronan Branch Line.

Cronk is next, and once leaving the station, trains cross a viaduct, and then arrive at Maron. They then descend Gordon's Hill and pass through two junctions that led to the Coaling Plant and the Suddery Junction, the junction to Edward's Branch Line, respectively. After passing Wellsworth, the Cow Field is next, where James once had his first accident with the runaway trucks and when half of Edward’s cattle train was broken by some cows in the cow fields. Then, the trains arrive at Crosby. After that, trains later pass through a mile-long tunnel and then stop at Knapford, the junction to Thomas' Branch Line. Crossing another tunnel, the main line passes Lower Tidmouth and terminates at Tidmouth.

Engines
The line is staffed by Gordon, who usually pulls fast passenger trains, Henry and James, two mixed-traffic engines, and Edward, who assists with lighter passenger duties and sometimes helps out with shunting duties and goods trains when not working on the Brendam Branch Line, Alfred also helps out from time to time with extra trains.