In order to be able to replace the outdated vehicles of the West Berlin S-Bahn, the BVG had the class 480 developed in the 1980s. Due to the special requirements in Berlin, completely new vehicles had to be developed that could benefit from the latest technology. A 90 kW three-phase motor was used on all axles, which enabled faster acceleration with lower losses. The smallest unit is the so-called “quarter train”, which consists of two permanently connected vehicles, each with a cab. One to four of these are coupled together during operation.

Since the class 481 was developed for the entire Berlin after reunification, only 85 quarter trains were built. The trains were nicknamed “Toasters”. After the introduction of the newer vehicles, they were no longer used across the entire network. However, since they are still needed, they were modernized between 2015 and 2018. From 2020 they also received the BVG's new train control system.

The class 423 was the first in a series of S-Bahn multiple units that had been purchased since the late 1990s to replace the aging class 420. Although the latter had been built up to that point, it was a 1960's design and the first examples had already reached the end of their useful life.

In contrast to its predecessor, the class 423 consists of four instead of three cars with the same overall length. While each car previously had two bogies of its own, the middle cars now rest on shared Jakobs bogies. This is just one of the weight reduction measures used, which reduced the curb weight by a total of 24 tonnes with the same number of seats. With 50 kW less motor power, acceleration was also significantly improved compared to the newer, weight-optimized versions of the 420 series. Four of the five bogies have two powered axles. The gangways between the cars are now open, which, among other things, enables a better distribution of passengers. With now three instead of four double doors per side, the total number of doors remained the same to enable quick entry and exit.

The vehicles quickly got the nickname “Quietschie” (from the German word for “squeak”), which came about due to a special feature of the combined power and brake lever. When starting off quickly, this is responsible for brakes still being applied lightly when the power is already switched on and therefore make a squeaking noise.

The classes 424 and 425 followed in 1999, which are identical to the class 423 in terms of length and power train. The different classes can be explained by minor adjustments for different areas of application. The class 425 has a toilet, fewer doors and different entry heights so that it can also be used outside the actual S-Bahn network. Some classes have LZB and are allowed to run at 160 km/h. The class 426 is a two-car version of the 425 with two of the three bogies powered. This is used for routes with low passenger volume and to reinforce existing trains. The most modern variant is the class 422, which has been built for the Rhine-Ruhr S-Bahn since 2007. The most important change is the adaptation of the vehicle fronts to the latest crash standards, which has increased the overall length by around two meters with additional crumple zones and anti-climbing devices.

There were some delays in the certification, which were caused, among other things, by a lack of braking performance in bad weather, software problems and problems with the door locking systems. By 2010, over 600 trains had been completed, of which 462 belonged to the class 423. Since 2013, some trains have been optically adapted to the even more modern class 430, which, in addition to LED lighting and an expanded passenger information system, also includes improvements in accessibility.

The class 430 is a four-car multiple unit for S-Bahn trains that was developed jointly by Alstom and Bombardier as the successor to the class 422 and, above all, replaced the last trains of class 420. The model was originally only planned for use in the Stuttgart network, but later the production of the 422 for the Rhine-Ruhr network was also discontinued in favor of further development. Ultimately, however, the Stadler FLIRT 3 was ordered there. A second area of application was found for it with the S-Bahn Rhein-Main.

The class 430 is based directly on its predecessor, but has improvements in many areas. In principle, the same three-phase asynchronous traction motors were used, but they and the entire chassis were further optimized in terms of smooth running, background noise and energy efficiency. Energy recovery from the electric brakes is also standard and benefits from the strong acceleration and deceleration in S-Bahn operation. The train is still running on five bogies, three of which are designed as Jakobs bogies between the individual cars. Except for the central bogie, all axles are powered. The design has been updated inside and out and includes new crash standards, LED lighting and a modern passenger information system.

As with other new rail vehicles in recent years, there were several delays in the course of certification and introduction, which in this case largely affected the locking mechanism of the doors. Finally, regular operation in the Stuttgart network could be started by the turn of the year 2013/2014 and the first tests and training courses were due in the Rhine-Main area at that time. A total of 188 trains were built up to 2017 and in 2021 production for the Stuttgart network was restarted and new trains were also ordered for the S-bahn Rhein-Main, which are to be delivered in 2023. The existing trains have been optimized in terms of software over time, which means, for example, that aggregates that are not required are temporarily switched off and the opening times of the doors have been reduced. Some of the previous classes are also being adapted to the design of the 430 series.

Towards the end of the 1960s, the Bundesbahn had the first S-Bahn multiple-unit train developed for alternating current networks, which was initially to run as the ET 20 with middle cars designated as the ET 21. The first services were to take place at the 1972 Summer Olympics in Munich. The first trains were given the class numbers 420 and 421 when they were put into service.

Each train consisted of three cars that had no gangways between them. In the middle car there was a first-class compartment, which was later either halved or completely replaced by second-class due to lack of demand. The sets could be coupled to form longer trains with little effort using Scharfenberg couplings. From the start, the middle cars were made of aluminum, and later the end cars were also made of aluminum instead of steel. All axles of the three cars were driven by nose-suspended motors and controlled by thyristors. Braking was usually electric and air brakes were only supplementary.

The production of the total of 480 sets was carried out by several manufacturers and lasted for a period of 28 years. These trains were used on virtually all West German S-Bahn networks that are electrified with the usual AC system via overhead lines and do not have their own DC system via third rail. In addition to Munich, these were also the S-Bahns Rhein-Ruhr, Rhein-Main, Frankfurt and Stuttgart.

The points of criticism of the trains that were repeatedly cited were that there were no gangways between the cars, the individual sets always had to be used with three carsand there were no toilets for longer sections. For this reason, some trains of the Rhine-Ruhr S-Bahn were handed over to Munich as early as 1980.

The class 420 trains were partly replaced by locomotive-hauled trains, but mostly by class 422, 423 and 430 multiple units. Some trains which had already been decommissioned were handed over to other regions when there was additional demand there. Some trains were used from 2002 in the Stockholm area as SL X420 and were scrapped in 2005. In 2006, two trains were upgraded inside and out as “ET 420 Plus”, but no other trains were converted. Although some are still in use today, 400 of the 480 sets have already been scrapped.

The class 270 of the Reichsbahn and later 485 of the Deutsche Bahn designates EMUs for the Berlin S-Bahn, which have been developed since the late seventies. They were ordered because of the problem that the fleet at that time was completely pre-war and a new model presented in 1959 had not gone into series production.

During development, care was taken to ensure that the external dimensions of the new cars corresponded as closely as possible to those of the old ones. This ensured that they could be dispatched in the same way in the company and that nothing had to be changed in the workshops. On the technical side, on the other hand, new achievements were used. Energy consumption was reduced by around 30 percent, primarily through lightweight construction and an electric regenerative brake. 

Although the prototype was presented at the Leipzig Spring Fair in 1980, the pilot series was not built until 1987. Series production took place from 1990 to 1992 with each 158 power cars and trailers instead of the originally planned 300 units. Instead, more examples of the West Berlin class 480 were procured. Nevertheless, the series was still not dispensable after 2010, partly due to failures and problems with newer series.

As a result, some that had already been parked were later reactivated and from 2015 there were even modernization measures. The latter included conversions in the area of radio, passenger information system and drive and brake equipment and should ensure that the vehicles can be used until at least 2023. Due to the additional equipment, the weight increased on individual bogies, which required a conversion of the service compartments. Nevertheless, due to the lack of the new train control system, the trains have not been able to be used on the Stadtbahn since 2018. This was an additional reason why general inspections have not been carried out since 2020 and the trains are to be parked when the deadline expires.

A further development was the Duo-S-Bahn, which was also equipped with underfloor diesel generators to bridge sections without conductor rails. However, since use on main routes together with faster trains would have been difficult and there was no further need, this model did not go into series production.

Between 1924 and 1932, the Reichsbahn procured a series of new railcars for the Hamburg-Altona city and suburban railway, which had been electrified with 6,300 V and 25 Hz since 1907, in order to supplement the existing fleet of railcars and to partially replace the steam trains.

Similar to the older railcars, the new ones consisted of individual compartments for second and third class, each with its own door on each side, as was standard for Prussian compartment coaches at the time. This time, however, the car bodies were constructed in a more modern all-steel construction with barrel roofs. Each unit consisted of two parts with a total of three two-axle bogies, of which the middle one between the cars was designed as a Jakobs bogie. The end bogie of one of the two cars was powered on both axles with a total of 300 kW. All electrical equipment came from BBC (Brown, Boveri & Cie.), while the mechanical components came from Waggonfabrik Wismar, WUMAG (Görlitz) and WASSEG (AEG/SSW).

When the new S-Bahn with direct current via conductor rails was introduced on the same tracks from 1940, the vehicle generations with overhead lines and conductor rails were operated in parallel to these. AC operation was discontinued in 1955 without a planned renaming to ET 99. Only two of the vehicles were converted to baggage railcars for the new power system and designated ET 174 001 and 002 by the Bundesbahn. These were scrapped in 1967.

The ET 165 is a class of pre-war railcars for the Berlin S-Bahn, which to this day has the highest number of railcars in Germany. They were built in a short period of time between 1928 and 1931 and were in daily use until 1997.

The vehicle concept envisaged that two cars, which always remain coupled together in everyday life, form a so-called quarter train and up to four of these quarter trains are connected depending on demand. Since each part had its own power train, the same power-to-weight ratio was available for every train length. Each quarter train consisted of one motor car and one control car. Later, the control cars were replaced by trailers and all existing control cars were converted to trailers. The power supply via third rail had the advantage that the vehicles were supplied directly with 750 volts DC and no longer needed their own transformers. Each of the two bogies of the motor car had two nose-suspended motors connected in series, which were each operated with 375 volts. Furthermore, weight was saved by making the load-bearing parts in a new alloy and the cars were around seven to nine tonnes lighter than their predecessors.

638 motor cars, 465 control cars and 173 trailers were built, which quickly dominated traffic on the Berlin S-Bahn. There were still a few teething problems, such as the wooden doors, which often warped, and the bogies needed improvement, but these were gradually fixed. As a result of the war, some vehicles came to various eastern countries, where some of them remained in use for a long time.

In the post-war period, traffic in both parts of Berlin was rebuilt with these vehicles. In West Berlin in particular, their number fell continuously in the 1970s and 1980s, as large numbers of new vehicles were procured and the existing vehicles were only modernized to a limited extent. Nevertheless, some were still in service after the takeover by Deutsche Bahn AG and were used until 1997 as the class 475/875 together with their sisters from East Berlin.

In the east, a large part of the vehicles had been reconstructed from 1979, as had already happened with the successor class. In addition to the interior design, the front sides were also modernized. The vehicles converted in this way were renamed from class 275 to 276¹ and were only retired in 1997 together with the West Berlin vehicles.

The ET 65, which was known as the elT 12 until 1940, was a multiple unit for suburban traffic in Stuttgart. Although more modern railcars were developed shortly after it, it was able to remain in service with several conversions from 1933 to 1979. Due to the noise of the traction motors, it was known to the population as the “Red Howler”.

The trains originally consisted of a power car with two pantographs, two intermediate cars and a driving trailer. Two-axle Württemberg passenger cars, which had been equipped with electric heating, were used as intermediate cars. The vehicles had multiple controls and were therefore given gangways on the front sides. In contrast to later models, there was still an auxiliary engine room inside the cabin of the railcar, since the electrical system was still too bulky at that time. The car bodies were still riveted, only the last series received welded superstructures.

After the war, two power cars and several driving trailers hab been destroyed, but these were replaced by vehicles from other classes. At the beginning of the 1960s, a modernization took place, in which the front sides were replaced by a common front without a gangway. The speed was increased to 85 km/h with new traction motors. In the second class there were now also upholstered seats and the two old intermediate trailers were replaced by an old refurbished four-axle car, one of the so-called “Umbauwagen”. With the introduction of computer numbering, the railcars became the 465 class and the intermediate and driving trailers became the 865 class. After they had been replaced by the 420 class and were decommissioned in 1978, they were retired in 1979.