Editing Heritage railway (section)

=== Mountain railways ===
{{main|Mountain railway}}
Creating passages for trains up steep hills and through [[mountain]] regions offers many obstacles which call for technical solutions. [[Steep grade railway]] technologies and extensive [[tunnel]]ing may be employed. The use of [[narrow gauge railways|narrow gauge]] allows tighter [[curve]]s in the track, and offers a smaller [[structure gauge]] and tunnel size. At high altitudes, construction and logistical difficulties, limited urban development and demand for transport and special rolling-stock requirements have left many [[mountain railway]]s unmodernized. The engineering feats of past railway builders and views of pristine mountain scenes have made many railways in mountainous areas profitable tourist attractions.