An engine with a crane on his boiler named Harvey arrives, but the engines think he does not look anything like a normal engine. Harvey becomes reluctant to stay, but has his chance when Percy derails at Bulgy's Bridge.

Harold helps Percy deliver his mail, but Percy believes he is under threat. When he reaches a broken signal, he is forced to wait until the signal is fixed. He is even more upset when Harold comes to take his mail onward. Harold decides to take the mail all at once - with disastrous results.