Percy's Accident is a magazine story.
On a cold morning, Thomas sets off to collect a train of milk tankers. Percy teases Thomas about it, but Thomas ignores him. Later, Percy is taking a passenger train down the line. He sees Thomas and the milk ahead of him. Unknown to Percy, the points are frozen and he goes sliding into the last tanker. No one is hurt but the tanker bursts into pieces and Percy is covered in milk. Back at the sheds, Thomas laughs at the cold and wet Percy while Sir Topham Hatt reminds the engines to take care in the cold weather.