I've greatly enjoyed "Mixed Train Daily" and also "The Steam Locomotive in America" by Alfred Bruce, last Director of Steam Engineering at Alco, however Tony Rolt's "Railway Adventure" is my all time favourite.
Tony Rolt had already written "Narrow Boat" the book which rekindled interest in canals in UK and was a prominent vintage car protagonist when he became the driving force and first General Manager of the regeneration of the Talyllyn Railway in mid-Wales and this book is his personal account of the first year's (1951-2) operation under the new management.
You may get the flavour of it when you hear that they found at the end of the first year's operations that the only thing holding the rails to gauge was the grass and moss, the timber sleepers (ties) having rotted long ago. It's certainly a blow by blow, no holds barred, account of arguably the first ever railway preservation -- note 'arguably', I'm not going to endorse any claims.
Bob Gartside