Arry and Bert

Arry and Bert are twin diesel engines in Thomas & Friends who work at the Sodor Ironworks.

Bad Qualities

 * 1) In their first appearance, they literally tried to scrap Stepney, and they nearly succeeded in doing so. To make matters worse, they were not caught. How worse can they get?!
 * 2) While they were portrayed as menacing villains when they debuted in Season 5, from Season 6 onwards, they were reduced to just regular school bullies, a primary example being the infamous Season 6 episode "Middle Engine".
 * 3) They were at their absolute worst in "Calling All Engines!", as they caused so much trouble that they nearly caused the summer to be ruined, and they acted like jerks.
 * 4) Most of the time, they don't receive any consequences for their bad behavior.
 * 5) Since they're nothing more than stereotypical bullies and all they do is stand around not doing a lot, they barely have any interesting characteristics to them.

Good Qualities

 * 1) They did end up paying for their bad behavior in "Halloween", "Percy's New Whistle" and "Thomas and the Stinky Cheese".
 * 2) In their debut in Season 5, they were portrayed as evil diesels who brought engines to the scrapyard to be scrapped. Unfortunately, however, that was a rarity in the show, as from Season 6 onwards, they were watered down to just generic bullies.
 * 3) At least they're intentionally portrayed as antagonists for the most part.
 * 4) Sometimes, they can do good things, and their are times where they redeem themselves, just like Diesel.
 * 5) Like most of the engines, their designs are neat and fitting in both the model era and the CGI era.