Troublesome Trucks (Foolish Freight Cars, or simply Freight Cars, in the US) are so nicknamed because they can be quite troublesome and love to play tricks on the engines, except Edward, Stepney, Hiro, and Salty as they have been the cause of many accidents. However since Douglas smashed the Spiteful Brakevan and Oliver pulled S. C. Ruffey, their leader, apart, they are frightened of some engines.
There have, however, been some cases where the trucks and engines are on the same side, such as when Diesel was given a third chance on Sodor, but the trucks tricked him into misbehaving and getting sent away again.
Trucks could be considered the rebels of the railway, as most of them love to cause mischief and trouble. They will play tricks on an engine based on how they treat them. Most accidents caused by the trucks are a form of revenge due to mistreatment. If an engine is having a bad day, makes a mistake, or is easily played upon, then the trucks begin their wild antics of singing, name calling, holding back, shoving, bumping, giggling and so on.
Trucks can also be described as territorial; when they get used to certain engines pulling them, another engine in the yard to take them may cause confusion or anger for the trucks. In Percy's Predicament for example, Toby and Percy switched jobs, making Toby's trucks furious and causing Percy to crash.
The Troublesome Trucks are mostly 7 plank and 8 plank end door open wagons. The van variety are mostly BR 12 ton twin ventilated and BR 12 ton single vent vans with corrugated ends.
Trucks are traditionally painted either dark grey, dark green, or brown with black frames, although in recent years, they have also appeared in red, green, blue, pink, and many other colours. Privately-owned trucks typically have their own specific livery.
Trucks are mostly utilised for the transportation of quarry rock and coal. Due to their ubiquitous nature on the railway, they have been employed for carrying a variety of other materials, such as wood, sand, china clay, bricks, and even debris after large storms. In more recent seasons, they have been used to transport specific goods which would be better suited for closed wagons; some of these goods include books, cocoa powder, presents, and raw fish.
- The Troublesome Trucks became Pooh's Enemies in Pooh's Adventures of Thomas & Friends: The Adventure Begins.
- The Troublesome Trucks will meet Ash Ketchum, Littlefoot, Simba, SpongeBob, Tai and their friends in Ash's Adventures of Thomas & Friends: The Adventure Begins.
- Trucks are never named; however, those that are privately owned tend to take on the name of their owner, like S. C. Ruffey, Fred Pelhay, U. L. P., Bennett and Co. and possibly Rickety.
- From the sixth season onwards in the US, the term "truck" is used more often. In more recent seasons, however, the US has been more consistent in using the term "car."
- In the first season of the television series, the trucks had their faces embedded into their bodies, much like Annie and Clarabel. From the second season onward, they were given face masks to allow a greater variety of facial expressions.
- The trucks were to have a larger role in Thomas and the Magic Railroad, but they were cut from the final film.
- From the twelfth season onwards, all the troublesome trucks have the same face design. In addition, the black and grey trucks are the only trucks to have faces.
- Since the CGI switchover, the open-topped trucks have become taller.
- During the fourteenth and fifteenth seasons, the trucks didn't have faces. They regained them in the sixteenth season.
- Until King of the Railway, the Troublesome Trucks caused no accidents after the ninth season episode Emily Knows Best, and had no speaking roles after the twelfth season.
- According to the Railway Series book, Oliver the Western Engine, ballast trucks are considered to be the worst of all.
- Some facemasks of Toad, Bulstrode, and the Spiteful Brakevan have been seen on the trucks.
- The Freight Cars are partners of The Changelings.