P.T. Boomer, also incorrectly known as Pete Boom, or Boomer, was a villainous character expected to be the main antagonist seen in Thomas and the Magic Railroad, but was cut from the film as test audiences complained that he was too scary and was replaced by Diesel 10, who was later rewritten as the main villain. He appeared in the trailer for the film, however. His role was played by late Canadian actor Doug Lennox.
P.T. Boomer was jealous of the relationship that Burnett Stone had with Tasha and bullied Burnett into allowing him to take Lady for a run. After crashing her, he left Shining Time Station while Burnett spent years trying to restore her, to no avail. Boomer is described in the script as being "a drifter through choice, not circumstance". He returns now a good forty years later a bitter and dark character bent on getting rid of Lady.
Boomer is the reason behind Mutt's unease, and reason for bringing Lily to Shining Time rather than letting her go on to Muffle Mountain. Boomer spends much of his time throughout the movie arguing with Burnett Stone and digging into the mountain looking for Lady.
He has no (said) ownership or connections with Diesel 10, other than their shared desire to destroy Lady and the Island of Sodor. He does not believe in magic and when he finds Thomas in the real world, he believes that he's just a huge toy. Thomas is the reason why Boomer ends up on Sodor: he's transported back in Thomas's cab on the way back through The Magic Railroad. When Thomas, Diesel 10, and Lady arrive back on Sodor, Diesel 10 attempts to grab Thomas with his claw, but instead accidentally grabs Boomer. Upset with his bad aim, Diesel 10 simply places Boomer onto his roof and continues chasing Thomas and Lady.
He and Diesel 10 meet their fates during the chase scene when they plunge off the viaduct into a barge filled with sludge. He spits out water and stares angry at Diesel 10 who says nothing, but looks at him sad. Much like in the final film, they are towed away on it, but in the original script, they are transformed into sludge by way of Junior's magic bandana.
When audiences complained about him being "too scary" he was cut out at the last minute, explaining the laziness of the movie's final cut. In the final cut, he can be found as the motorcycle rider that Burnett was in the process of giving directions (in the original cut the two were having a row). Even so, something seemed very dark about said character. Additionally, during the chase sequence, he can be seen lying on the back of Diesel 10's cab in several scenes. Boomer was also present in a trailer for the movie, falling off the viaduct with Diesel 10.
Many scenes pointing towards his role are seen as well, such as Billy Twofeathers holding flowers while speaking with Stacy. In the said scene Billy and Mutt encounter P.T. Boomer waiting for them on the Shining Time Station platform. After a confrontational exchange about Burnett Stone's whereabouts and being stonewalled by Billy, an enraged Boomer leaves, but not before taking a swing at the hanging flower basket that Mr. Conductor had watered earlier. The script describes Billy picking up the flowers that have dropped onto the ground.
Also, while driving Lily to see Burnett, Stacy is seen holding a photograph. Even though in the movie it's not clear as to what it is, according to the original script, it was a picture of a younger Burnett and Tasha during a school dance with P.T. Boomer angrily eying the couple.
Also, after Billy Twofeathers waves to the children, in the original cut, from Billy's point of view he would see a motorcyclist (Boomer) racing across the hillside. He purposely cuts in front of the train at the crossing, startling Billy to apply the brakes and blow the locomotive's whistle. The tense atmosphere of this shot was enhanced by Britt Allcroft including a flock of panicked birds suddenly taking flight upon hearing the whistle's shriek.