The "Coffee Pots" were constructed and designed at Tidmouth by a young Sir Topham Hatt when he was an engineer to the Tidmouth, Knapford and Elsbridge Railway. They were designed as four small 0-4-0 tank engines with vertical boilers that were nicknamed "Coffee Pots". This was partly due to the fact they resembled coffee pots, and they were prone to cough up dirty brown water.
The Tidmouth, Knapford and Elsbridge Railway eventually became part of the North Western Railway. With the formation of the new main line these engines were relegated to only operate between Elsbridge and the east side of the bay platform at Knapford. Between 1924-5 the branch line was extended to Ffarquhar and Anopha Quarry, these engines were used by the North Western Railway to pull trucks from Anopha Quarry, but were worn out soon after Thomas was given charge of their branch line. After a probationary period at Wellsworth, the Coffee Pots were transferred back to Thomas' Branch Line and served the line as back up. The Coffee Pots are mostly used for shunting, but sometimes they pull light freight trains.