SOLVED. YA Puzzle Mystery novel/ detectives. A group of kids or teens embarks in the adventure of solving a mystery involving the reader who must decide where they go.

[Victoria]

I read this book in the early 2000s but it was an old book, maybe from 1980 to the 90s, the cover was green and black, very similar to penguin crime hardcovers around that time. (maybe like this: https://www.pinterest.com/pin/7388786...)

I remember it included a punch card in the shape of goggles that you could use to read code and you jumped around pages based on what you decided the group would do next.

[Victoria]

solved in Reddit: https://www.enidblytonsociety.co.uk/b...

The haunted railway game, Enid Blyton.

[Rainbowheart]

Glad you found it!

The Haunted Railway Game for the GR link.