The Sodor China Clay Company, also known as the China Clay Works, the China Clay Workings, the Sodor China Clay Pits, or just the 'Clay Pits, is a company situated near Brendam. It owns Bill and Ben, and uses them to carry china clay from the Clay Pits along a private line to Brendam Harbour.
It first appeared in the second season and appeared regularly until Bill and Ben relocated to Anopha Quarry in the fifth season. It was mentioned in the seventeenth season episode Gone Fishing that Bill and Ben work at the Clay Pits once again. This was confirmed in Tale of the Brave, when the Clay Pits returned in CGI with Timothy accompanying Bill and Ben. Marion also works here.
Mr. Perkins also mentions the Clay Pits when teaching Archie Higginbottom how to be an engine driver.
In the third season, the Clay Pits were struck with a large avalanche. Luckily, Bill and Ben were able to help evacuate the Clay Pits before anyone was injured. In Tale of the Brave there were two avalanches, the first Bill and Ben rescued Thomas from and another near the end which involved Percy.