A double railway tunnel near Wałbrzych in the Dolnośląskie Voivodeship. The tunnels are located under the Mały Wołowiec mountain (720 m above sea level), in the south-eastern part of the Wałbrzyskie Mountains in the Black Mountains range between the towns of Wałbrzych and Jedlina-Zdrój on the railway route from Wałbrzych to Kłodzko. They are one of the longest tunnels in Poland. These are two parallel, straight, single-track, single-track railway tunnels drilled under Mały Wołowiec (720 m above sea level). The first 1560 m long tunnel was drilled in the years 1876–1879. The second, parallel one, with a record length of 1601 m, was dug in the years 1907–1912 The tunnel inlets are located at an altitude of 535 and 540 m above sea level, and their decline towards the south-east is 3.12 per mille. The maximum depth of the tunnels from the surface is 181 m. The tunnels are made of stone blocks, partly of clinker bricks, and sometimes with reinforced concrete elements. The portals of the inlets to the tunnel were finished in a stone casing made of wedges. The shape of the tunnels is elliptical, width 4.8 m, height 5.8 m. On the sides of the tunnels, several escapes and inspection recesses of the tunnel drainage system were made. In order to remove the exhaust gases, a ventilation shaft (chimney) for ventilation was drilled in the rock in the rock, and between the parallel tunnels, five connecting points were made (of which three remain open to this day), which at the same time constitute emergency recesses. The decisive influence on the construction of the tunnel was the Franco-Prussian war, which showed the importance of the railway at that time. After completion, the original concepts for the construction of the Wałbrzych – Kłodzko railway line, one of the sections of the Silesian Mountain Railway, were returned to. One of the many obstacles on the route was the Mały Wołowiec massif (720 m above sea level) in Rybnik Ridge, separating the Wałbrzych Basin from the Noworudzki Depression. In order to cross it, it was decided to bore a single-track tunnel with a length of 1560 m in a brick lining. The first works began in the summer of 1876 and lasted until 1879. The first train officially passed through the tunnel on October 15, 1880, after all, work on the single-track route had been completed. At the end of the 19th century, it was decided to build a second parallel track. In 1909, the construction of a second parallel tunnel, 1601 m long, with parameters similar to the previously made tunnel, began. The tunnel was put into operation in 1912. The tunnel, which was first put into operation, was shut down in the late 1990s.