For various reasons, such as copyright and/or personal interests, certain fans of Thomas & Friends have kept the existence of Behind-the-Scenes material from the television programme a secret.
Below is a list of gatekept material we only know the existence of:
Stills from the Down the Mine Pilot episode[]
Starting with 2020, rumours that the staff members of the Sodor Island Forums own information about the production of the Down the Mine Pilot episode started circulating on Twitter.
In 2022, a development of this rumour started circulating, according to which SiF staff member Ryan Hagan had shown a number of stills from the Pilot to a number of fans. This new, very specific rumour, stated that the SiF own a picture of the Knapford set built for the Pilot, along with one of Thomas, Annie and Clarabel on the so-called "intro bridge" set, facing away the camera.
Shortly thereafter, Twitter user @fan100_thomas discovered that, on the box of the 1984 Merit board game The Magic Turntable, a still from the Pilot episode of the Knapford set, appearing to match the description featured in this new version of the rumour, can be found - although it is partially obscured by a cutout of a clock.
When the script of the Pilot episode was revealed by Twitter user @UlfsteadEstate in December 2022, fans started noticing the similarity between the description of one of the stills SiF apparently own, and a passage in the script, which reads as follows:
"EXT. Top of the Bridge, Reverse of S. C. 3 - Thomas puffs away from us. Clarabel has a down expression."
The unavailability of the script at the time of the rumour's initial circulation has led multiple fans to believe it is true.
Information About the O gauge Test Shoots[]
According to Stephen Asquith, before filming the ”Down the Mine” Pilot Episode, using gauge 1 models, the crew of Thomas the Tank Engine experimented filming with O gauge models. They used O gauge PECO tracks for this test.
In a conversation with an anonymous Twitter user, from 2021, former Thomas & Friends prop collector @TomsProps revealed, in a concealed manner, the existence of this O gauge test shoot. Due to the wording of this message, it appeared as if he'd just made an assumption it might've existed.
In 2023, former Twitter user @FlyingPringle confirmed that Tomsprops did, in fact, have evidence supporting the theory that O gauge, indeed, was the originally proposed gauge the programme was supposed to be filmed in.
Along with @FlyingPringle, users @fan100_thomas and @Ryans0ck compiled every bit of information available about this test shoot into a document.