Engerth locomotive
The Engerth locomotive was a type of early articulated steam locomotive designed by Wilhelm Freiherr von Engerth for use on the Semmering Railway in Austria. The distinctive feature of the Engerth design was an articulated tender as part of the main locomotive frame. Some of the weight of the tender therefore rested on the driving wheels, improving adhesion, while articulation allowed the locomotive to navigate the narrow curves of mountain railways. Designer Wilhelm von Engerth was born in Pless, Upper Silesia (Now Pszczyna, Poland) on 26 May 1814, the brother of the artist Edouard von Engerth. Initially, he studied architecture, but in 1834 he took up mechanical engineering as a profession. By the late 1850s he was the General Manager of the Imperial Austrian State Railways. Von Engerth was created a Baron (Freiherr) in 1875, and he died on 4 September 1884 in Leesdorf. History Von Engerth first patented his design for an articulated locomotive on 11 December 1852. Semmering The Semmering Railway, opened on 17 July 1854, was one of the first true mountain railways, traversing a section of the Austrian Alps. It was characterized by steep gradients and sharp curves. To work this railway a new design of locomotive was developed. A competition was held to decide which locomotives would be bought for operation on the Semmering Railway. One stretch of the line had gradients of 1 in 40 (2.5%) and curves with a minimum radius of and a maximum radius of . A speed of was required to be maintained and a maximum axle loading of 14 tonnes, with a boiler pressure not exceeding 8.5 kgf/cm² (830 kPa). There were four entrants, Bavaria, built by Maffei; Wiener-Neustadt built by Wiener-Neustadt; Seraing built by Société anonyme John Cockerill in Belgium and Vindobona built by the Gloggnitz Bahn in Vienna. All four locomotives met the trial conditions, but none proved reliable in practical use. The Semmering Trials led to a number of developments in locomotive design: Fairlie's Patent of 1863, The Meyer locomotive and the Mallet locomotive. The Engerth design articulated the tender with the main locomotive frame, allowing some of the weight of the fuel and water to be carried on the driving wheels to improve adhesion. Because the tender was articulated, rather than directly attached to the frame, the locomotive could traverse relatively sharp curves, while still enjoying the advantage of the additional adhesive weight gain. The original design also included an indirect drive from the main driving wheels to the wheels under the tender. This arrangement proved too complex to maintain and was dropped from the design. Sixteen locomotives were supplied to the Semmering Railway between November 1853 and May 1854. They proved capable of uphill on gradients of 1 in 40 (2.5%). An Engerth locomotive was featured on an Austrian stamp commemorating the 150th anniversary of the Semmering Railway in 2004. The Engerth locomotive also appeared on a 25 Euro coin issued by Austria in 2004. Other Engerth locomotives The design proved popular, especially for