During the mid-1960s, BR was looking to introduce a high-powered diesel loco to improve services on the West Coast Main Line. Although the new Class 47s would have perhaps been the first choice, these were already proving unreliable and suffered regular engine failures. Subsequently, BR opted to lease 50 locomotives from English Electric instead. Initially known as English Electric Type 4s, the locos were purchased outright by BR at the end of the lease and became known as Class 50s.When Class 50s were introduced onto Britain's railways, they were regarded as poor substitutes for the beloved Western Region diesel hydraulics they were sent to replace. However, as time went on, they impressed more and more. In fact, towards the end of their careers, they developed a following not unlike the last days of the hydraulics, with many enthusiasts clamoring to photograph or ride behind them. The interest in the class is still evident to this day, with as many as 18 still surviving in various states of repair. Including over 200 images, this volume shows the class at work around the UK, covering not only the BR era, but also subsequent years.