Complex sentence: Soon after, the railway was extended to Mödling and Neunkirchen and on 5 May 1842, the line from "Wien Südbahnhof" (Southern Station) was completed up to Gloggnitz at the northern foot of the Semmering Pass.
Split into simpler sentences: Soon after, the railway was extended to Mödling and Neunkirchen. The line from "Wien Südbahnhof" (Southern Station) was completed to Gloggnitz at the northern foot of the Semmering Pass.