The Lost Spring is a magazine story.
The Island of Sodor is having a heatwave and Farmer McColl's crops need lots of water. Terence helps by pulling a cart with a huge water barrel on it around the field. Farmer McColl worries that if the heatwave continues, he may run out of water. He then tells Terence that there is an underground spring on his farm somewhere and if he could find it, he would have plenty of water.
Soon Bill and Ben pull up side-by-side at a signal on their way to Brendam Bay. Farmer McColl had gone for lunch and left Terence resting under the shade of a tree. The signal changed and Bill and Ben puff away. After lunch, Farmer McColl returns. Terence sets to work, but chugs too close to the slope at the edge of the field. Terence's caterpillar tracks allow him to keep a good grip, but the cart tips over and the water barrel rolls away. It lands on the railway line just as Bill and Ben are returning. They decide to race each other back to the main station, unaware of the danger on the line ahead. As Ben takes the lead, he sees the water barrel in front of him and brakes hard. Ben bounces right off the rails and across the grass, ending up with his buffers ploughing deeply into the corner of Farmer McColl's field. Terence and Farmer McColl arrive at the scene of the incident and after making sure Ben is safe, Terence cannot help but joke that he is supposed to plough the field, not Ben.
Suddenly, Ben feels water begin to bubble up through the ground and around his wheels. Farmer McColl is delighted; Ben had found his spring. Bill fetches Rocky and soon Ben is back on the rails. Ben is soaked, but is happy that he will soon dry thanks to the heatwave. Terence is delighted; thanks to Ben, Farmer McColl's crops are saved.
- The back part of Bill and Ben's cabs are coloured brown and their roofs black.