102 meters is too long: Why only short trains work on Berlin's U4!

To understand this, you have to go back more than 115 years. Today's U4 was not planned as part of a large, integrated Berlin network, but as the independent underground railway of the then still self-governing city of Schöneberg. On December 1, 1910, the line, only around 2.9 kilometers long, between Nollendorfplatz and today's Innsbrucker Platz station entered service. It consisted of five stations and was initially even separate from the rest of Berlin's elevated and underground railway network.

At the time, this small urban service did not need platforms where a modern eight-car train could stop. Some stations were therefore built with only around 45 meters of platform length . This included Viktoria-Luise-Platz and today's Innsbrucker Platz. That was entirely sufficient for the short trains of the Schöneberg railway at the time. It was only later, when the line was to be more closely connected to Berlin's network, that several platforms were extended.

Around 1920, some facilities were therefore extended to approximately 90 meters. One reason was to allow longer six-car trains to operate and to facilitate better connections to the rest of the narrow-profile network. As a result, the U4 had significantly more space than when it opened, but it nevertheless remained a line with comparatively short stations. Even today, the platform lengths of various U4 stations are roughly in the range of around 90 to just under 100 meters.

And this is exactly where SubwaySim 2 comes into play. The A3L92 included in the game already consists of a double railcar in its smallest formation. Such a unit is approximately 25.7 meters long. Couple two of them, and you reach around 51 meters. Three units already reach just under 77 meters – and with four units, the train reaches approximately 102.6 meters in length.

This quickly makes it clear why the four-unit formation no longer works on the U4. Such a train would be longer than the usable platform length at several stations. The game is therefore not arbitrarily preventing a particular configuration, but is reproducing a real restriction of the line. Especially important: “4x A3L92” does not mean four individual cars, but four double railcars – eight cars in total.

In normal timetable operations, you can therefore operate the U4 with one or two A3L92 double railcars . In Sandbox mode, a triple formation can also be used. The nearly 77 meters still fit, but already appear noticeably larger at the short stations. With four units, that is definitively the limit.

The situation is similar with the other vehicles. A single HK already consists of four cars and is slightly more than 51 meters long. That fits on the line. A double HK unit, on the other hand, would once again exceed 100 meters and would therefore be too long. A single four-car unit of the Gisela is also approximately 51 meters long and is therefore suitable for the U4. Several such units would likewise exceed the available platform length.

This is also where a problem arose that some players encountered after release. Anyone who had already selected a formation that was too long before choosing a route could get the impression that the U4 was not included in the normal timetable at all or was playable only through scenarios. In fact, the line can be played regularly – the game simply does not offer it for train configurations that do not fit the short stations.

This is particularly noticeable at Innsbrucker Platz. The U4 is the only line that runs there. If the selected formation is not permitted, the most obvious starting point of the new line is therefore missing at the same time. At Nollendorfplatz, it can be overlooked more easily among the other lines operating there.

What is interesting is that SubwaySim 2 does not simply smooth over the line's historical peculiarity. In theory, the developers could have extended the platforms in the game or allowed trains that were too long to stop anyway. Instead, the real construction history has a direct impact on vehicle selection. A decision made in 1910 thus becomes a genuine game mechanic more than a century later.

And that is exactly what makes the U4 more interesting than its mere four stations might initially suggest. It is not simply a shorter version of a normal Berlin U-Bahn line, but was built under completely different conditions and has remained to this day a distinctly short-train line. The fact that a 102-meter-long train does not fit is therefore less of an obstacle – and instead a remarkably consistent form of realism.

Has the U4 in SubwaySim 2 ever failed to appear for you because of a train formation that was too long? Do you think it is good that real platform lengths actually restrict vehicle selection – and do you prefer driving a short train, or do you use 3x A3L92 in Sandbox mode to make full use of the available space?