Branch Line Coaches are smaller coaches that are used for smaller trains on the branch line. However some coaches are used on the main line for slower trains.
Like the express coaches and the slip coaches, none of these coaches are given names in the series. But they are given lines and have faces similar to Annie and Clarabel.
There was a coach named Koby specifically built for Thomas' Branch Line, but he proved to be a troublemaker, so he was sent to a field by Wellsworth. He has a face similer to Annie and Clarabel. The rest of the coaches are known to be behave well, though.