Steepest railway gradient (adhesion)

The steepest grade traversed by an adhesion railway (one driven by the friction of wheels on rails) is 1 in 7.2 (13.8%; or around 7.9 degrees of angle). This is found on a street called the Calçada de São Francisco in Lisbon, Portugal, which is part of line 28 of the Lisbon Tramway System.

The urban tramway network of Lisbon was originally a cable-driven system – like the streetcars of San Francisco in the USA - but was converted to electric traction in the first few years of the 20th century.

The steep climb up the Calçada de São Francisco is around 180 m (590 ft). Because of the extreme grades the trams have to negotiate on line 28, the rolling stock consists of single-carriage streetcars, instead of the larger articulated units used on other lines.

As the tracks have to follow the grades and curves of existing roadways, urban tram networks make up the majority of the top ten steepest railway gradients worldwide.