The Railway Series: Surprise Packet was a Railway Series related activity book which featured stories, games, posters, and puzzles.
- Sodor Railway Poster
- Tidmouth Grand Tour
- How to make a Working Model of Skarloey
- How does a Steam Engine work?
- The First Railway Engine
- How to Drive James
- How Sharp are Your Eyes?
- Bill and Ben, Bothering!
- Knapford Junction Game
- Thomas' Branch Line
- A Trip on the Culdee Fell Mountain Railway
- Problem Page
- Here Be Steam Engines!
- Answers Page
- Culdee's driver is revealed to be named Joe.
- A fourth open carriage can be seen on Peter Sam's train.
- This book marks the first mention of the "Coffee Pots" and Elsie.
- The North Western Railway has its own headcode and signalling indications.
- On the Tidmouth Grand Tour, Bear is depicted with a grey white face, rather than his yellow one.
- On the "Problem Page", Percy has Henry's nameplate, and his saddletank is vaguely different. James is missing his tender and a splasher. Gordon has a blue running board and is also missing his tender.
- In Tank Engine Thomas Again, Henry has a brass funnel, a Fowler tender, square buffers, and two sided-windows on his cab. Awdry explained that after Henry was released from the tunnel he needed to go to the Works, but the Works could not afford the special parts, so they had used Gordon's spare parts instead. Because of this, people mistook him for Gordon.
- In The Three Railway Engines, the fourth illustration of Edward's Day Out features a coach without a front coupling. Awdry explained that one of the big engines was pulling the coaches so roughly that the coupling fell off. When Edward arrived to collect the coaches, they hadn't fitted a new coupling and hook. This took some time, so the guard went off home to his "elevenses". This also explains as to why Edward was waiting for his guard.
- In the map of Thomas' Branch Line, the location where Daisy meets Champion seems to be near Dryaw at the harbour line. This is incorrect, since the Island of Sodor: Its People, History and Railways mentions it to be after Elsbridge. Also, Daisy cannot take passengers on the harbour line.