It is difficult to define the center of Berlin, given that until 30 years ago the city was divided, but most Berliners would grudgingly accept that Alexanderplatz - the center of the former Soviet quarter - is probably it. The train station Berlin Südkreuz, situated in the south of the city in the district of Tempelhof-Schöneberg in the old west, is an important stop on many international and national trains and lies around five miles (7.5 kilometers) south-southwest of Alexanderplatz. The station is old, originally opening in 1898, and gets the 'Kreuz' part of its name from the fact that it acts as an intersection, with platforms running both north to south and east to west. Services from the train station Berlin Südkreuz run north to Hamburg, Rostock and Kiel and south to Munich and Nuremberg. Passengers can also travel west to Essen or Cologne. Südkreuz is easily accessible by public transport.
There is a range of options to choose from when getting from Alexanderplatz to the train station Berlin Südkreuz. Although the station is not on the U-Bahn (the Berlin subway), it is on the S-Bahn, which is Berlin's (mostly) overground train service, with the S41, S45, S46, S2, S25, and S26 all serving the station. To get the S-Bahn from Alexanderplatz, passengers should board the S3, S5, S7, or S9 to Friedrichstraße Bahnhof and change there to the S2, S25, or S26 southbound, which will take them straight to the train station Berlin Südkreuz. Passengers can also take the U8 to Hermannstraße in Neukölln, and from there, they can get the S41, S45, or S46 west to Südkreuz. There is a direct bus to Südkreuz from Alexanderplatz - the 248 - that runs every 10 minutes throughout the day. If traveling at night, the S-Bahn is not such a good option, because it is fairly irregular. A better option would be to take the N42 bus, which runs from Alexanderplatz to Kolonnenbrücke, from where the station is a 15-minute walk down a main road. A taxi is also an option.
Usually, the fastest way to cover the five miles between Alexanderplatz and Südkreuz is to take the S-Bahn, catching the S3, S5, S7, or S9 to Friedrichstraße Bahnhof and then boarding the S2, S25, or S26 to Südkreuz. Unless there are delays on the line (which there sometimes are) this should take around 25 minutes. The option of taking the U8 and then the S-Bahn only takes a couple of minutes more, but you do have to change sections of the station when you change trains at Hermannstraße. The 248 bus typically takes around 45 minutes, depending on traffic, which will be less at night and more at rush hour. A taxi is likely to take around 23 minutes in light traffic. It's also worth noting that if passengers are staying away from Alexanderplatz, Südkreuz is on what's known as the 'Ringbahn', the S41 and S42, which runs continuously around the perimeter of the city center. If passengers are unsure how to get to Südkreuz, they should just go to the nearest station on the Ringbahn and they'll get there eventually.
Südkreuz is fully accessible for those with limited mobility. It has elevators between the platforms and street level, as well as between levels in the station. There are also markings on platforms for those with impaired vision. Berlin's transport system is extremely accessible and one of the best equipped in Europe for those with limited mobility. Friedrichstraße Bahnhof and Alexanderplatz Bahnhof are both fully accessible, as is Hermannstraße. The bus services in Berlin are fully accessible, with ramps to let wheelchairs on, and space inside for wheelchair users to sit in. The S- and U-Bahn trains tend to be a little more spacious than the buses, so for users with a large amount of luggage they are probably a better option, although the trains can get busy at rush hour.
There is plenty to see in and around Südkreuz. The station is around 20 minutes walk from Tempelhofer Feld, the site of the old Berlin airport. The terminal building has been left untouched, and tourists can take a tour around it - this is the airport into which the Allies flew supplies into Berlin during the Berlin Airlift. If passengers are around in the late afternoon, the Feld is a great place to watch the sunset. There is also a large - and rather sweet - 'colony' of allotments tended to by residents of Berlin who don't have their own gardens. Tourists can walk through the 'Kolonie Sonnenbad', although not through the gardens themselves.