While enthusiasm for the great days of steam shows no sign of waning , those days ended more than 40 years ago, and the era that followed it on Britain 's railways is now all but over as well - the era of the diesel (or electric) hauled train . Just as any SO year period of railway history saw dramatic and far-reaching changes during the steam age, so the last SO years has seen progress that goes far beyond just a change in the principal form of traction . Today's privatised railway system is operated almost exclusively by multiple-units on passenger trains and a limited number of classes of modern high-powered diesels for freight traffic. Even the nominally locomotive-hauled (or propelled) trains such as the High-Speed Trains and the East Coast Main Line electrics , highly successful as they are, hold little appeal to the traditional railway enthusiast. The circumstances of privatisation, though, have led to a revival in the fortunes of some of the classes of 'first-generation' diesels which had previously all but disappeared.