During the latter half of the 1800s, railways were laid through forests and landscapes, over water, and through mountains. The engineers' task was to design a route with gentle curves and as little gradient as possible. The curves were to have a radius of at least 300 metres, and the maximum gradient of the track normally did not exceed 10 per mille.

Excavation work was done by hand and often involved cuttings and embankments in the terrain. There needed to be a balance between what was excavated and what needed to be filled in. When the landscape could not be altered, the solution was to build a bridge or a tunnel.

Initially, railway bridges were constructed of wood. It was inexpensive, but maintenance quickly became extensive. Smaller bridges were also built in stone, similar in construction and appearance to the arched stone bridges of peasant Sweden, but they were time-consuming and expensive to build. Steel also appeared early on as a material for bridge construction, and from the 1910s onwards, concrete became common. These two materials then became dominant in bridge construction.

As early as the late 1850s, the first railway tunnels began to be constructed in Nyboda outside Stockholm and Bränninge outside Södertälje. The tunnels were blasted through the mountains. The projects were extremely extensive and costly for the time. As early as the 1870s, there were ideas about a tunnel through the Hallandsås ridge. It was concluded that the project was desirable but not feasible. 140 years later, the tunnel could finally open.

Caption: Wooden Bridge over the Dal River 1874