DBAG Class 423
| Company type | Electric multiple unit train |
|---|---|
| Industry | Rail transport |
| Founded | 1999 |
Area served | Germany |
| Products | Electric multiple units for S-Bahn commuter rail systems |
Deutsche Bahn Class 423
The Deutsche Bahn Class 423 represents a lightweight, articulated electric multiple unit (EMU) tailored for Germany’s S-Bahn commuter rail systems. While it maintains dimensions comparable to its forerunner, the Class 420, it is notably lighter and features a single expansive passenger area instead of the three-compartment design found in the 420. Each car is equipped with six doors (three on each side), a reduction from the eight doors per car seen on the Class 420. The fleet is numbered from 423 001 up to 423 462.
Several major German metropolitan areas, such as Munich and Frankfurt, procured Class 423 trains to serve their S-Bahn networks, with deliveries spanning from 1999 through 2004. This model has served as a blueprint for a series of related units deployed throughout Germany’s S-Bahn systems, including the Class 422, Class 424, Class 425/426, and Class 430.
Description
A typical Class 423 trainset comprises four cars connected by three jacobs bogies, which can only be separated during maintenance procedures. The two middle cars are classified as Class 433. The usual composition of a unit is:
- 423 x
- 433 x
- 433 (x+500)
- 423 (x+500)
For example: 423 194 + 433 194 + 433 694 + 423 694. Variations in formation occur when partially damaged trainsets are combined.
Two of these short units coupled together form what is known as a "full train," while three units make up a "long train."
The design allows unobstructed visibility from one end of the train to the other. Initially, a lockable door located centrally permitted closing off part of the train during periods of low ridership to increase passenger density and enhance social monitoring. Passenger information displays provide details about destinations and upcoming stops, complemented by audio announcements indicating which side doors will open. An automated door monitoring system using light barriers facilitates driver relief by eliminating manual door checks; this system was temporarily disabled in 2007 until retrofitting with light grids was completed.
The front lighting system consists of three-light headlights capable of switching between low and high beam settings during travel. Certain Munich S-Bahn units (specifically 423 238 and 423 268) were fitted with LED headlights combining green and red LEDs to achieve a balanced spectral output; however, subsequent modernization efforts replaced these with warm white LED modules across the entire fleet.
Each side of the train features twelve doors, each measuring approximately 1300 mm wide. Door activation is managed through electronic pushbuttons that provide visual release confirmation via LEDs and respond to mechanical pressure. Originally, these buttons were thumb-sized and only provided visual feedback. In March 2012, capacitive pushbuttons with larger surfaces, illuminated rings, and audible signals were trialed on unit 423 089 in Munich before being installed fleet-wide during modernization.
The production of this series was divided into five delivery batches:
- First batch: units 423 001–190
- Second batch: units 423 191–305
- Third batch: units 423 306–371
- Fourth batch: units 423 372–396
- Fifth batch: units 423 397–462
Units numbered from 423 444 to 456, manufactured in 2007, only entered operational service in early 2010 due to issues related to door safety.
The Class 422, developed as an evolution of the Class 423, was delivered between 2008 and 2010. It features an extended vehicle front section that adds two meters in length compared to Classes 420 and 423. The later Class 430 series—based on the Class 422 design and introduced from 2012 onwards—is only about ninety centimeters longer than Classes 420 and 423, allowing long trains to fit within standard platform lengths of approximately 210 meters.
Technology
These multiple units are powered by eight water-cooled, four-pole, three-phase asynchronous traction motors, collectively generating 2350 kilowatts. Their two mostly independent traction systems share energy through a single pantograph.
The initial series (423 001 - 423 190) is equipped with GTO inverters, whereas series two through five utilize IGBT inverters, which produce a noticeably higher-pitched sound from the traction motors on the IGBT-equipped trains.
Each unit contains a pair of central control modules. Communication between these modules is facilitated by a multifunction vehicle bus and a wire train bus capable of data transfer rates up to one megabit per second, supporting automatic train set identification and configuration. Safety features include an emergency brake system along with an emergency brake override function.
For service braking, electrodynamic brakes are employed alongside an electro-pneumatic brake system consisting of 16 cylinders, six of which incorporate spring accumulators.