It is commonly referred to as the world's first true mountain railway, given the very difficult terrain and the considerable altitude difference that was mastered during its construction.

Across an overall track length of 41 km the Semmering railway overcomes an altitude difference of 460 m; on 60% of its length the gradient is 2.0-2.5% (equivalent to a 1-meter difference in altitude on a 40 m route distance) and 16% exhibit a curvature radius of only 190 m. This was an entirely new technical dimension of railway construction, and new instruments and methods of surveying had to be developed to handle the resulting challenges.

Also, new technologies were employed for the Engerth locomotives because the types in general use at this time could not handle the extreme gradients and turning radii.

Even while being built, the Semmering railway was perceived as an effort of "landscape gardening", i.e. it attempted a harmonious combination of technology and nature.

A trip on the Semmering railway, which is in full use 160 years after its building, still impresses the traveller as a special experience by its varied landscape, the typical style of its mansions and the characteristic sequence of viaducts and tunnels.

[2] The Engerth design articulated the tender with the main locomotive frame, allowing some of the weight of the fuel and water to be carried on the driving wheels to improve adhesion.

Because the tender was articulated, rather than directly attached to the frame, the locomotive could traverse relatively sharp curves, while still enjoying the advantage of the additional adhesive weight gain.

The 1967 Austrian schilling note features the engineer on one side, and a Semmering scene (including one of the distinctive two-tier bridges) on the other.