ABSTRACT
Long two-axle vehicles, and other vehicles with several wheelsets incorporated in a single frame (a so-called rigid wheelbase), like locomotives, have obvious limitations in curves. The first known proposal for the bogie was made in Britain by William Chapman in 1797 [1]. It was, however, in the United States that the concept was first employed to a significant extent. Dissatisfied with the performance of the rigid wheelbase British locomotives on the lightly built and curvaceous American track, John B. Jervis with advice from Horatio Allen designed the first locomotive with a leading swivelling bogie in 1832. In this, two wheelsets were mounted in a frame which was free to swivel without restraint relative to the main body of the locomotive. This radically improved curving behaviour [2]. In addition to its application to locomotives, passenger coaches employed bogies in North America from the 1840s. These early bogies had very short wheelbases and tended to oscillate violently being the probable cause of many derailments. In the 1850s the wheelbase of the leading truck of locomotives was increased which improved stability significantly [3]. In Britain with relatively straight track there was little need for the use of bogies until trains increased in size in the 1860s, and in any case the few occasions when bogies had been used gave them a bad reputation with British railway engineers. Fernihough pointed out the danger of bogie oscillation in his evidence before the Gauge Commission in 1845 [4] and suggested that it might be controlled by the frictional resistance of a bearing ring of large diameter supporting the car body on the bogie, an idea subsequently adopted widely. The centre friction plate, or alternatively, friction at the side bearers, provided yaw restraint for small relative motions thus preventing bogie hunting on straight track at currently prevailing speeds. On sharp curves, at low speeds, the friction was overcome and the bogie was able to take up a more radial position on the track. In the case of bogie passenger coaches it was appreciated that isolation of the car body from motions of the bogie required some form of secondary suspension. So, in addition to a secondary vertical suspension, the swing bolster which provided lateral flexibility between bogie and car body, was invented by Davenport in 1841 [5]. In Britain, though the use of bogies in locomotives was exceptional until the 1870s, those that were built often incorporated lateral movement of the bogie pivot restrained by some form of spring, called a centring spring [6].
