The Adventures of Thomas was a planned theatrical Thomas & Friends film. According to director Shane Acker, the film was eventually cancelled after being pushed back several times following Mattel's acquisition of HIT Entertainment.
The film would have taken place in London during World War II, and revolved around a pre-teen boy who has drifted apart from his father. The son is introduced into the world of Sodor, a place his father visited as a child but cannot remember. There is a bonding experience.
It has also been confirmed that it would have involved a steam vs. diesel confrontation.
- The movie was originally scheduled for a "late 2010" release, but was pushed back to Spring 2011, then to a 2012 release, then to a 2013 release and finally a 2014 release before eventually being cancelled.
- The film would have used a combination of live action (most likely humans) and CGI. Weta Digital was going to supply the CGI aspect of the film. The E2 portrayed in the teaser poster however was made by Nitrogen Studios.
- The film was going create its own line of toys aimed at an older audience.
- This film was to be the first in a potential series which would run alongside the television series.
- WETA Workshop and Mattel Entertainment Design Group, the creative team behind the movie, are "re-imagining the core characters and the world in a way that will appeal to a wide kids and family audience."
- It appeared that the movie would have been distributed by Cinetic Media and UTA's Independent Film Group in conjunction with HiT Entertainment.
- According to the Sodor Island Fansite, the script was written and completed in 2010. 
- In 2021, further images showcasing an early version of the model used in the poster were released, however it featured some noteworthy differences:
- Whereas the final model has a painted number, the early model had a brass numberplate.
- The early version of the model is painted a much more saturated shade of blue.
- The final model features additional rivets on the valences, running board, side tanks and bunker.
- This would have been the first time Thomas was portrayed with a rear running board dip (outside of some merchandise lines) and a Westinghouse air brake pump, both of which were features on the real LB&SCR E2s but were never shown to be carried by Thomas.