This book provides, in a compact form, the very basic knowledge in the science of railway operation in a close connection to signalling principles and traffic control technologies. It was written both as a tutorial for students of railway-related programs and as a reference for people in the industry. Although written from an European point of view, this book tries an independent look at railway operation without concentrating on the operating philosophy of a single railway. But where it makes sense, it is always mentioned if an operating procedure or signalling principle could only be found in a specific country or groups of countries.