The cog railway is in the region of Achaea and connects the area of Diakopto with Kalavryta.

The Cog Railway first opened in 1896 and since then daily crosses the Vouraikos gorge, connecting Diakopto with Kalavryta, stopping in Niamata, Triklia, Kato Zachlorou (Great Cave) and Kerpini. The route of the Cog Railway is 22.350 m and lasts about an hour.

The railway is named "cog", due to the cogged,toothed rails it has in multiple parts of the route. Owing to the steep slope that reaches even 17.5%, the train is hooked on rack rails on each point with a slope over 10% and continues its path. Because of its difficulty of manufacture, the width of the cog's line is only 75 cm, making it one of the smallest in Europe. In the straight track, the train speed reaches 40 km per hour, while where it meets slope it drops to 12 km per hour.

The technical characteristics of the Cog Railway are quite interesting, but its most important feature is the actual route. A majestic route into and through nature. The train passes through the gorge of Vouraikos, through impressive tunnels with stalagmites it meets waterfalls and unique vegetation, making the trip a memorable experience.