The "Main Line" runs from Knapford to Vicarstown, and then onto Barrow-in-Furness in England.
The Main Line is obviously the busiest line on Sodor. It is served by many different trains. There is a high speed service from Knapford to London Kings Cross Station, with a stop in Elsbridge and Wellsworth before it reaches the mainland. There are several nonstop express trains from Knapford to Vicarstown as well limited stop ones, mainly pulled by Gordon. Then of course, there are the local trains that stop at every station. These are often pulled by James and Henry.
- Knapford (connection to Ffarquhar Branch & Little Western)
- Tidmouth (connection to Ffarquhar Branch & Little Western)
- Elsbridge (connection to Ffarquhar Branch)
- Wellsworth (connection to Brendam Branch)
- Killdane (connection to Peel Godred Branch)
- Kellsthorpe (connection to Kirk Ronan Line)
- Crovan's Gate (connection to Skarloey Railway & Norramby Branch)
- Vicarstown (connection to Norramby Branch)
- Barrow-in-Furness (connection to railways in England)
The following engines work on the main line