Culdee is a purple mountain engine who works on the Culdee Fell Railway.
Ironically, after Rheneas told Sir Handel about a mountain railway, Donald arrives with Culdee from the Culdee Fell Railway. Culdee told Sir Handel about when he was tested by an inspector, and later, he told him as well as Duncan about Godred, a grumpy mountain engine who fell off a mountain and was later used for spare parts.
When Culdee arrived back on the Culdee Fell Railway, Ernest and Wilfred told him that three new engines arrived: Alaric and Eric are nice quiet engine, but Lord Harry's a terror! Lord Harry soon learnt his lesson and was stripped from his name. No. 6 soon redeemed himself by rescuing some climbers, and was renamed Patrick.