In the late 1840s the British engineer Thomas Russell Crampton sought a means of reducing the left-right oscillation then dangerously affecting locomotive stability. His solution was to place the drive axle behind the engine, near the boiler, and give it wide-diameter wheels. During the conclusive first trials in 1846 the Namur and Liège locomotives reached speeds of 100 km/h. Although considered too aggressive by other continental railways, the Crampton locomotives were much appreciated in France. In 1848, the engineer Jules Petiet ordered several for the Northern Railway. The performances of these ‘rail greyhounds’ in terms of speed and fuel consumption were excellent, but their weak adherence posed problems when drawing heavy trains. From the 1880s they were gradually replaced by locomotives with coupled drive axles.