Railway buffs looking for a fix have an abundance of choices throughout Switzerland, particularly during summer.
And among the more famous railways favoured by visitors - such as the railway to the Junfraujoch - are some less-well known gems.
Near the central-Swiss city of Luzern is one of the world's oldest cog railways, and it opens in May.
Climbing over 2,000 meters to the top of Mount Pilatus, the railway has an average gradient of 48 per cent - one of the steepest of its kind anywhere.
The 1889-vintage track starts from the town of Alpnachstad, and offers breathtaking views en-route to the summit.
First in the Alps
Nearby is the Vitznau-Rigi railway - the first of its kind in the Alps.
Founded by Swiss engineer Niklaus Riggenbach, who patented the world's first cog-spoke system in 1863, the railway was opened in 1871, to worldwide acclaim.
While the line is among several ways to reach the top of the 1752-meter Mount Rigi-Kulm, it remains historically the most significant.
Top of Europe
Those visiting the nearby Bernese Oberland, only an hour or so from Luzern, could take a ride on the Jungfrau Railway, open all year.
This line climbs from the Kleine Scheidegg on cog railway through the heart of the Eiger Mountain to Europe's higest railway terminal - at 3454 meters.
The Jungfrau railway takes visitors through the newly-listed Unesco world natural heritage site, the Jungfrau-Aletsch-Bietschhorn region.
Built more than 100 years ago, the railway remains one of the most popular, and atmospheric, in Europe.
Nearby, and on the rail-link between Interlaken and Luzern, is the Brienz Rothorn railway, which opens for the warmer months from the end of May.
The Rothorn Railway is Switzerland's oldest steam-powered cog line. It has been steaming its way up the 1,678-meter hill since 1892, during the golden age of early Swiss tourist development.
At the top, visitors have access to the Rothorn Kulm Hotel, 360-degree mountain views, and alpine hikes.