Cable haulage did prove viable where the gradients were exceptionally steep, such as the 1 in 8 gradients of the Cromford and High Peak Railway opened in 1830. Cable railways generally have two tracks with loaded wagons on one track partially balanced by empty wagons on the other, to minimise fuel costs for the stationary engine. Various kinds of rack railway were developed to overcome the lack of friction of conventional locomotives on steep gradients.
