The Bernina Express crosses from Switzerland into Italy over 196 bridges and through 55 tunnels, climbing the highest rail route in the Alps. The film follows the train through the Graubünden Alps in winter, tracking its path through deep valleys, glacier-carved gorges, and stretches of permanent ice that make the line an engineering gamble even now. It traces the line back to 1890, when engineers first closed the gap through southeastern Switzerland, a project that meant blasting tunnels through granite and building viaducts across ravines with no modern machinery. Footage shot from the train and from vantage points along the route shows snow drifts, exposed curves, and the sheer drops the track was built along. The film treats the Bernina line as both a tourist marvel and a genuine feat of survival engineering, showing how avalanches, ice, and rockfall still shape how and when the trains run. It is part of a series profiling the world's most hazardous rail routes.