From the introduction: Cavern of the Sub-Train is a scenario set in the Gamma Terra gaming environment. This module has been adapted to my Masters of the Earth Campaign from the original written by Gary "Jake" Jaquet. I have attempted to keep the original text whenever possible except where it was required to match my specific campaign requirements. It has been designed for use by 3-8 players of levels 3-6, being optimal. The adventure begins in the ruins of Lorns North East of the city state of Boze. Life in the city state has been rather uneventful, other than the usual dangers of the environment. Recently, however, a most unusual discovery has been made, one which will shortly send player characters on an exciting and dangerous adventure.