Genoa is blessed with a feast of unconventional rail systems that would satisfy any rail enthusiast for days. this particular narrow gauge railway runs from the suburb of Manin in the city of Genoa to a small mountain settlement in the Ligurian Apennines about 20 miles away. It follows a circuitous route that tracks the natural contours of the landscape as much as possible, resulting in outstanding panoramic views.

The railway was originally intended as a passenger line to complement a proposed freight line. The many stops along the line to Casella led to its success as a commuter service for Genoese workers who live in the mountains. It was first proposed in the late 19th century and authorization was given in 1915, just in time for it to be delayed by Italy's entry into World War I. Construction did not start until 1921 and today's terminus in the center of Castella was not opened until 1980.

For rail enthusiasts, there is another fascinating aspect to this line. Narrow gauge railways in Italy generally run on the Italian meter gauge, which is 950 mm between the inner rail edges and 1,000 mm between rail centers. With the (never-realized) intention of connecting to the Genoa tram network at Manin, such a gauge was adopted for this railroad. There are only about half a dozen railways like this in Italy, of which only two were built without either a funicular or a rack and pinion element.

The zig-zag element on this line operates in and out of the Casella Deposito station and is a means of gradually changing height over a short distance.