British Rail Main Line Locomotives Specification Guide identifies the major detail differences and livery variations that have appeared on all British Rail, ex-British Rail and privatized railway diesel and electric main line classes from 14 to 92. The book provides a record of the main specifications of each class of locomotive, and details of variations, including: numbers, liveries, headcodes, headlights, wheel arrangements and bogies, brakes, names and - where appropriate - details of refurbishment programmes.