Mail Coaches are a type of coach used to transport letters and parcels. They form The Mail Train, which is usually pulled by either Thomas or Percy. Oliver was once briefly transferred to the service and at times when the train is unable to run, Harold usually deputises for it. Since being transferred to the Harwick Branch Line, Daisy takes a mail coach from Arlesburgh up to Harwick every morning. They are used at night, but in recent seasons, the coaches are pulled in broad daylight. Since the seventeenth season, however, they seems to be pulled primarily at night again. Percy is almost always in charge, although other engines pull them occasionally.
The Mail Coaches are based on British Railways' General Utility Vans (GUVs), previously known as Covered Carriage Trucks (CCTs). These vans were designed primarily for the transportation of letters and parcels and based on the BR Mark 2 coach design.
In the Railway Series, the Mail Coaches were painted plain brown. In the television series, the Mail Coaches are painted crimson with grey roofs. In the Model Series, they had "SODOR MAIL" on both sides, but was changed to an envelope with wings in the CGI Series.
- All the mail coaches' models are currently on display at Drayton Manor. One used to be on display in Canada at Nitrogen Studios.
- From the third to fifth season, the mail coaches were made out of Tenmille gauge 1 Utility van kits. From the sixth season onwards, they were scratch built.
- In the third and fourth seasons, two separate trains were pulled by Thomas and Percy as the load was too heavy for one engine to do the work alone.
- The mail coaches have gone through a couple modifications over the years:
- Season 6:
- Their roofs became slightly larger.
- Their bufferbeams are lowered.
- They became slightly taller.
- Their liveries became slightly darker.
- Hero of the Rails:
- Their "SODOR MAIL" logos were replaced with envelopes with wings.
- Season 6:
- ERTL (discontinued)
- Wooden Railway (discontinued)
- Take-n-Play (with Pull 'n 'zoom Percy)
- Motor Road and Rail (discontinued)
- TrackMaster (normal and see-inside)
- Motorized Railway
- Take Along (discontinued)
- Collectible Railway
- Hornby (two versions; discontinued)
- Wind-Up (reintroduced; Japan only)
- Thomas Engine Collection Series (with brake van; discontinued)
- Pocket Fantasy (discontinued)
- Nakayoshi (discontinued)
- Mega Bloks