The Little Engine's Big Day is a bedtime story book featured in Mr. Perkins' Sleepover.
The Little Blue Engine loves nothing more than puffing along the track pulling important loads. One day at a junction, he meets a Big Silver Engine, who calls him a "slow coach". The Little Blue Engine feels insulted and goes as fast as he can to prove the Big Silver Engine wrong. However, he comes off the tracks from going too fast. Once he was back on the tracks, he continues his journey carefully to the Docks, this time ignoring the Big Silver Engine's teasing. He is praised by the Dock Manager for being really useful and he toots happily with pride.
- The Little Blue Engine - An 0-6-0 well tank, who looks similar to Bash. He loves puffing along the track pulling important loads. He does not like being teased and is determined to prove others wrong, but strives to be really useful. According to Mr. Perkins, he acts similar to Thomas.
- The Big Silver Engine - A large tender engine. He enjoys teasing smaller engines and can be rather impatient. According to Mr. Perkins, he acts similar to Spencer.
- The Dock Manager - The manager of the Docks, where the engines work. He praises the Little Blue Engine for carefully delivering his load and calls him really useful.