Logan is a steam shunter.
Logan is based on a Radstock Sentinel Shunter. He happens to be colorblind, and upon his arrival on the Island of Sodor, he confused Edward and Gordon's identities. Logan has the appearance of a diesel due to his boxy shape, and some of the other engines at the coal plant like making light-hearted fun of it. He is a durable and strong shunter, who is hard-working and patient.