From the saucily snarling chords of Cabaret to the dusky, smoke-filled backrooms of Christopher Isherwood’s novels, 1920s Berlin conjures up certain images in the collective consciousness. And no city could cultivate an image as distinctive as Berlin’s during this period without a solid public transport network.

Yep, you guessed it. We’re here to talk about trains.

First things first, a reasonably brief history of the Berlin U-Bahn.

This map shows it pretty well, but the gist of it is that a very small-scale, east-west network was built by about 1913, running primarily through Schöneberg, Charlottenburg, and Wilmersdorf, all pretty affluent areas as it was thought this would prove more profitable. This wasn’t an entirely underground network, though, and the earliest stretches of track were elevated.

The second phase of construction, through the 1910s and 1920s, saw the first north-south lines, as the city wanted to bring the benefits of the railway lines to the city’s poorer residents.

Lisa Charlotte Rost, a blogger and data nut (same) living in Berlin, spotted this historical map from 1927 at Uhlandstrasse U-Bahn station in Germany’s capital, and it’s pretty cool.

The caption, written in the beautiful phlegm that is the German language, translates as, roughly: “Strength/density of traffic on the over and underground railway lines in 1927 (numbers given in millions of passengers)”

The first thing to note is that the lines pictured on the map are rather different to today’s U-Bahn offering.

The stretch from Thielplatz to Nordring is today split between two lines: the U3, from Thielplatz to Nollendorfplatz, and the U2, from there to Nordring, which is today called Schönhauser Allee.

The branch of the same line from Wittenbergplatz to both Stadion and Wilhelmplatz is now split between the U2, which runs from Wittenbergplatz to Olympiastadion (as it is now known) and on further to Ruhleben, and one stop of the U7 from Bismarckstrasse to Richard-Wagner-Platz, which appears on the 1927 map as Wilhelmplatz.

The light green line on the map, from Uhlandstrasse and Hauptstrasse to Warschauer Strasse, is today primarily the U1, which runs from Uhlandstrasse to Warschauer Straße. The spur from Nollendorfplatz south to Hauptstrasse is today the short U4 line, on which many of the station names have changed. Viktoria-Louise Platz and Bayerischer Platz have stayed the same, but Stadtpark has become Rathaus Schöneberg and the terminus, Hauptstrasse, has become Innsbrucker Platz.

The final principal route that this old cartographic wonder shows runs from Seestrasse in the north to Bergstrasse in the south, with a short branch running off to Flughafen (as in, airport) too. Seestrasse is now about one-third of the way along the U6 line, which runs south to Mehringdamm, which on the 1927 map is called Belle-Alliance Strasse. From there, the current U6 continues along the path of the short spur line to Flughafen, where Kreuzberg station is today’s Platz der Luftbrücke and Flughafen – built to serve the old Berlin Tempelhof airport, now used as a recreational park – which is today called Paradestrasse.

The main run of the dark green line on the 1927 map, however, meanders on via Hermannplatz and Rathaus Neukölln to its terminus at Bergstrasse, which is today called Karl-Marx-Strasse.

And finally there’s the little, little-used stretch from Kottbusser Tor south to Boddinstrasse, which is just a small chunk of today’s U8.

So yes. Lots of differences.

As for the real content of the map, there are lots of very obvious things to say here.

All three main arteries are much busier in their central sections than at their edges – fairly predictably.

Transfer stations such as Wittenbergplatz, Nollendorfplatz and Friedrichstadt all see slight reductions in the business of one line as passengers flip over to the other – again, standard.

Branch lines of the same route combine to make the central sections busier in terms of passenger numbers: Belle-Alliance Strasse sees 26.1m and 5.6m journeys combine, with a few others who get on at Belle-Alliance Strasse, to make 33.8m journeys from there to Hallesches Tor. This is also obvious.

But you can also pick out two interesting tidbits that reveal the age of this map in an enjoyable way.

The line to Flughafen looks pretty unused, and there are two obvious reasons for this. One is that air travel was nothing like it is today. Deutsche Luft Hansa (as in Lufthansa, but there’s no legal connection) has only started in 1926, and the U-Bahn connection to Tempelhof airport was the first direct connection between a metro system and an airport in the world. Air travel for passenger use was still in its very early days, and was restricted to those who could afford it.

The other important fact here is that the station only opened on 10 September 1927. By that measure, having already seen 2.2m journeys isn’t actually bad work.

The other interesting point on the map is the Stadion station, which only had 600,000 journeys in 1927, according to the map.

There’s no excuse of youth, here: the Stadion U-Bahn station opened on 8 June, 1913, at the same time as the Deutsches Stadion on the site.

The whole site was finished in ample time for Berlin’s hosting of the 1916 Summer Olympic Games, but they were cancelled for the obvious and glaring reason of the First World War, and regular train service to the Stadion station did not start until 1922. The surrounding area at that time was hardly (nor is it today) a particularly packed residential area, so it’s understandable that use of the station was a little dwindling.

It was only when Berlin was awarded the 1936 Olympics that the area came back to life. German architect Werner March was originally contracted to restore the 1913 Deutsches Stadion, but when Adolf Hitler came into power and decided to use the games as propaganda, he commissioned March instead to build a totally new stadium.

In 1927, however, the 1936 games hadn’t even been awarded to any city (next up on the horizon were the 1928 games, in Amsterdam).

So there you have it. History, maps and trains, all at the same time. Don’t say we never do anything for you.