1Andrew Fowler is a well known writer of railway history, with a regular feature in Railway Herald Magazine. The Deltic class 55 Locomotives were some of the most successful, first generation diesels introduced to British Railways, being constructed from 1960-1962 and numbering twenty two, in the production class. The prototype machine was constructed in 1956 and was tested extensively on express trains on the London Midland and Eastern Regions of B R, until 1960. The interest and enthusiasm, for the class is reflected in the fact, that six examples of the class are preserved, including the 1956 prototype. The Baby Deltics, were a derivative Locomotive design, using one rather then two engines, for use on outer suburban and short main line semi fast services. Only ten Baby Deltics were constructed between 1961-1962, for use on services out of London Kings Cross. The Baby Deltics were all withdrawn within a decade, as they were not very successful in main line service.