railography photo galleries : Spain : Ponferrada - Villablino : 79-PV01-0004 : (21 of 21)

An Interesting Engine

A view of No.11 on shed at Ponferrada on the morning of 21 December 1979.

These locos may look like conventional tender engines at first glance but they're actually quite sophisticated machines. Part of the weight of the tender is transferred to the main frames by means of a pair of beams extending from the front of the tender and resting on brackets behind the main drivers. This increases the weight on the driving wheels and improves adhesion. A beam and supporting bracket can be seen just to the left of the engineman in this picture.

The principle of transferring tender weight to the driving wheels dates back to the early 1850s when Wilhelm von Engerth used it in his design for the Semmering, Europe's first mountain main line. True Engerths have an articulated frame so the Ponferrada engines are probably best described as Krauss-Engerths after the German firm that developed the design into the more practical form seen here.

Also of note is the use of a Krauss-Helmholtz truck, a means of steering the locomotive into curves by using the lateral movement in the carrying axle to produce an opposite movement in the leading coupled wheels.