The photographs contained in this collection stem from an album named "protective structures along the Gotthard railway line" («Schutzbauten an der Gotthardlinie»). The Gotthard railway line is secured by a large number of walls, barriers, barrages and dams to protect rail traffic against natural hazards—especially rockfall and avalanches.The album was compiled by the SBB in 1935 from pictures taken between 1911 and 1923. Today it is part of the extensive photo archive of the Heritage Foundation SBB (SBB Historic). It was digitized in 2010.