text: The Class 66 is a type of six-axle diesel-electric freight locomotive developed in part from the , for use on UK railways. Since its introduction the class has been successful and has been sold to British and other European railway companies. In Continental Europe it is marketed as the EMD Class 66 (JT42CWR).
  History
  Background
  On the privatisation of British Rail's freight operations in 1996, Wisconsin Central Transportation Systems under the control of Ed Burkhardt bought a number of the newly privatised rail freight companies: Transrail Freight, Mainline Freight, Loadhaul, and later, Railfreight Distribution and Rail Express Systems; thus controlling 93% of UK rail freight. After a public relations exercise involving the input of the general public, the company was named English Welsh & Scottish Railway (EWS).
  EWS inherited a fleet of 1,600, mainly diesel, locomotives, with an average age of over 30 years; 300 had been cannibalised for spares. Typical of the fleet, the  Class 47s needed a major overhaul every seven years, costing £400,000; yet had an average daily availability of less than 65% with only 16 days between major failures. To enable it to offer its stated lower pricing to customers, EWS needed to reduce operating costs and increase availability.