The Diesel Directory is a series of programmes looking at the development of British Diesel Rail Traction. In the 1980s the independent stone producing company Foster Yeomans ordered a small series of locomotives from General motors of the USA. Delivered as Class 59 they became progenitors of all the subsequent orders by the privatised railway companies including ARC, National Power, EWS, Freightliner, DRS and GB Railfreight, all of whom bought either more class 59s or the class 66 variant to form the backbone of the British railway freight locomotive fleet in the 21st century.
Freightliner also pioneered a rebuild of the venerable class 57, which also spawned the only modern passenger locomotives, operated by Virgin and First great Western. Finally, EWS bought 30 class 67s for Postal traffic, which have since been seen on many other types of trains. All these classes are included here.