Mystery Bridge Nr. 93: The Unusual Railroad Truss Bridge (Or Bridges) In The Erzgebirge


ERLA-CRANDORF (SAXONY); GERMANY- Not far from the towns of Markersbach and Schwarzenberg is our next mystery bridge. This one is located over the Schwarzwasser River in the small town of Erla. First mentioned in the history books in 1308, Erla and its neighboring village Crandorf are located three kilometers southwest of Schwarzenberg. Combined, they have a population of only 2000 inhabitants, with Erla having 850. The two communities had been a joint entity from 1925 until it became part of the Schwarzenberg consortium in 1999, which remains to this day. While Crandorf is located on top of one of the mountains in the Erzgebirge, Erla is wedged deep in the Schwarzwasser Valley and is easily accessible by rail and by highway, both leading to Johanngeorgenstadt, which is at the border between Germany and the Czech Republic.

This bridge is one of the most unusual through trusses one can visit. It is located 50 meters from the train station and right next to the steelworks, which has existed as long as the community. When looking at the bridge from a distance, it appears a duo span that are siamese twins, meaning one truss bridge is connected to a larger truss span. Upon further view, the bridges are indeed separate, but the spans are different in size and age. The only similarity is that they are both Warren trusses with subdivided vertical beams, yet the larger one has a Scharper design.

The larger span features a through truss span with a 45° skewed portal bracings, which stretches three panels on the right side of the truss. Both the portal and the strut bracings are I-beamed shaped, while the first left panel has a vertical bedstead endpost and 60° heel bracings supporting the first strut and the portal bracings. All beams are mainly I-beam, with the vertical beams being H-beam. All connections are riveted. Every panel has a heel bracing on the bottom end of the decking. The bridge is 25-30 meters long and about 10 meters wide. It is taller than the neighboring pony truss bridge by 2 meters. The bridge is much newer with the only engraving being the name of the steelworks company, the Friedrichshutte, based in Laubach (Hesse), which is east of Frankfurt (Main). It is very likely that the bridge was built after German Reunification and is between 10 and 20 years old. But when it was built is unknown.

It is just as unknown as the pony truss span  located right next to it. The bridge is definitely older, yet the question is how old. The Schwarzenberg-Johanngeorgenstadt-Karlsbad route was built in 1883, and the railroad was rerouted between Erla and Schwarzenberg in 1946, which included the elimination of the tunnel going underneath the castle in Schwarzenberg. The chances of the pony truss span being built during Communist times is likely as riveted and welded trusses began to take over trusses with pinned connections in 1910. Bridges built to replace those destroyed during World War II were built using this type of connections on the trusses. This pony truss bridge has welded connections as it was built using T-beams. Even the gusset plates are welded into the beams making it sturdier. What is unique about the pony truss span is its unusual skewed span. It appears that the skew is 60°+ or misaligned by four panels, which makes it unusual for a skewed truss span. The vertical beams feature a pencil-like thin trapezoidal design, where the beam’s width is 25 cm, yet the beams narrow to form a pencil chewed on both ends- with 40 cm from the top and 25 cm from the bottom chord. The truss is 2 meters tall and the width is about eight meters. Because of its age and narrowness, it was subsequentially replaced but never removed. Even though it has been fenced off, it appears that a bike or pedestrian trail may be in the works in the long term, especially as there is a bike trail already in existence between Aue and Schwarzenberg. If it is the case, it may be an advantage for those wishing to bike up the mountains.

A photo gallery of the two bridges is available here. If you know more about the bridges, feel free to contact the Chronicles. The main questions to be answered are: What more do we know about the history of the bridges? What did they look like before 1945? When were the two bridges built? And in the case of the pony truss bridge, who was the bridge builder? Any ideas and help would be much appreciated.