Drip Tank is the sixth episode of the first season of Thomas' Adventures Chronicles.
Percy was thinking of telling Thoms and Toby about his good day when he gets scratched by a low tree branch. Thomas makes rude remarks about it and he and Percy decides not to speak to each other. A few days later, Percy asks Toby what a drip is, having heard a boy call his friend one at the platform, but Thomas interrupts and tells Percy he's a drip. Thomas soon gets his comeuppance when his side rod snaps and punctures his watertank on his way home. Twilight went to get Percy's help however he refuse to go after last night. But changed his mind when Twilight and Pinkie Pie remined him about Annie, Clarabel and the Passengers. When Percy goes to help him, Thomas feels ashamed and apologises to Percy and soon both engines become friends again.