In Tramway Engines, Mavis was particularly fond of putting the trucks in different places at the quarry. However, this created confusion for Toby and he left Mavis to her own devices. One day, the trucks were tried of being pushed around by Mavis. They took advantage of Mavis, and caused her to block the lane-way resulting a traffic jam. Another time, they bumped Toby and he ended up suspended over a raging torrent on a pair of dangling rails.
In Toby, Trucks and Trouble, they pushed Mavis into a lorry and that made extra work for Toby at the quarry while she was being mended. Terence had to take care of the shunting at Ffarquhar, while Percy had to do Toby's work as well as his own. However, the trucks managed to teach the highly disagreeable Bulstrode a lesson, when Percy accidentally pushed trucks off the quay and into his hull.