What the current Alexanderplatz station has to do with Berlin's market hall affairs:
Every year on March 13th, the birthday of its namesake, the Architects and Engineers Association of Berlin (AIV) awards the Schinkel Prize. This has been a tradition since 1854, across various categories. The prize is awarded to applicants under 35 years old and is given in recognition of outstanding technical and scientific achievements in the construction field.
The Schinkel Prize is preceded by the Schinkel Competition. In January 1874, the "Monthly Competition," a kind of monthly contest for the Schinkel Prize, focused on the theme of "Stations on Viaducts," specifically a station at Königsbrücke (today near Alexanderplatz station). For several years, discussions had taken place about building a "market hall in connection with the Königsbrücke-Kaiser Wilhelmstraße station of the Berlin City Railway," which was also to have a rail connection.
However, things didn’t move swiftly even back then. By June 1881, the rental issue resurfaced at the City Council Assembly, having been previously discussed in various mixed deputations (what we would now call committees). The Royal City Railway Directorate had long been negotiating with the magistrate, and adjacent private land had to be purchased. Regarding the extraordinary session on June 28, 1881, the Berliner Tageblatt reported on the deputation's proposal to the City Council Assembly: "The assembly authorizes the magistrate to rent the viaduct arches of the Royal City Railway, which are located at the Königsbrücke station and are offered to the Berlin City Commune for use by the Royal City Railway Directorate, at an annual rental price of no more than 10 marks per square meter of usable area. [...] and finally 3) to prepare a general plan for the construction of market halls for the entire city and to submit it to the assembly."
What remains of this plan today? If you travel from Hackescher Markt to Alexanderplatz station, you will notice a widening between Roch and Rosa-Luxemburg streets, just south of the long-distance railway tracks. This is where the tracks of the market hall connection once ran. The Monthly Competition proposals even suggested an elevator for freight cars to make unloading them at street level more efficient. To alleviate space constraints for shunting wagons, the competition drawings proposed a system of small turntables that would rotate wagons on their own axis, allowing them to be shifted to different tracks.
Another notable feature: the plans envisioned a much wider station. Each platform track (in red, except for the inner track) had boarding and alighting options on both sides. From today's perspective, the single staircase for accessing and exiting the platform seems hardly sufficient!
In the years that followed, Alexanderplatz station continued to serve as a canvas for architectural innovation.
Drawing: Architecture Museum of the Technical University, MK 38-057.