S45 is a line on the Berlin S-Bahn. It operates from Flughafen BER Terminal 1–2 beneath Berlin Brandenburg Airport to Südkreuz over: a very short section of the Outer ring, opened in 1951 and electrified in 1983, a short section of the former Outer freight ring opened in the early 1940s and electrified in 1983, the Görlitz line, opened in 1866 and electrified in 1929, the Baumschulenweg–Neukölln link line, opened on 8 June 1896 and electrified in 1928 and the Ring line, completed in 1877 and electrified in 1926. From Wikipedia
