The sleek lines of the HST 125 High Speed Train represent a massive stride in British locomotive design in the latter part of the twentieth century. With two power cars the HST - otherwise known as the British Rail Class 43 - has a top speed of 125 mph, making it the fastest diesel-powered train in the world at the time of its introduction. Although nearing the end of its service life, recent refurbishments will give the HST another ten years in mainline service. The story of the HST is a rare example of British design success. Developed in the 1970s at a time when the railways were in desperate need of modernization, it filled the gap left by the failure of the infamous APT tilting train to become the mainstay of highspeed rail travel for several decades.