DB Class 120

DB Class 120
Lars Steffens · CC BY-SA 2.0 · source
Name	DB Class 120
Powertype	Electric
Builddate	1979–1985
Builder	AEG, Krupp, BBC, Henschel
Totalproduction	60
Wheelarrangement	Bo-Bo
Length	16.80 m
Weight	83 t
Electricsystem	15 kV 16.7 Hz AC
Collectionmethod	Pantograph
Maxspeed	200 km/h
Poweroutput	4,400 kW
Operator	Deutsche Bundesbahn, Deutsche Bahn
Fleetnumbers	120 001–120 060

DB Class 120

The DB Class 120 was a pioneering German electric locomotive introduced by Deutsche Bundesbahn in the late 1970s and early 1980s. Designed as a high-performance four-axle loco, it combined innovations in power electronics, traction control, and ergonomics to influence subsequent Siemens and Bombardier designs as well as European locomotive practice. The type proved influential in linking developments at Technische Universität Berlin, industrial groups like AEG and Krupp, and operational needs from Frankfurt am Main to Hamburg corridors.

Development and design

Development began amid strategic discussions at Deutsche Bundesbahn and technical research at Technische Universität München and Technische Universität Berlin regarding future traction systems. Project management involved consortium members including AEG, Brown, Boveri & Cie (BBC), Krupp, and Henschel, with input from standards bodies such as Deutsches Institut für Normung. The design emphasized an early application of three-phase asynchronous traction motors controlled by thyristor and later gate turn-off technologies, influenced by theoretical work at Fraunhofer Society laboratories and practical experiments on prototypes like the DB Class 103.

Aerodynamic considerations drew on research from the German Aerospace Center and prototype styling trends popularized by Nürnberg Messe exhibitions. Cab ergonomics reflected recommendations from occupational studies associated with Bundesanstalt für Arbeitsschutz und Arbeitsmedizin, while bogie dynamics used data from vehicle testing at the Wegberg-Wildenrath Test and Validation Centre.

Technical specifications

The locomotive used a single-phase 15 kV 16.7 Hz overhead supply collected via pantograph and transformed through onboard step-down transformers developed by BBC. Power conversion relied on early three-phase inverters and pulse-width modulation techniques pioneered in collaboration with Siemens. Each Bo′Bo′ unit carried four asynchronous traction motors; control systems incorporated microprocessor logic that foreshadowed later implementations in EuroSprinter family members.

Key systems included regenerative braking compatible with continental grid standards overseen by Österreichische Bundesbahnen and load management compliant with signaling interfaces from Deutsche Reichsbahn research. Safety equipment integrated train protection features aligning with PZB standards and later retrofits for compatibility with LZB lines such as Cologne–Frankfurt high-speed line. Bogie design enabled 200 km/h maximum speed with axle loads calculated per guidelines from UIC committees.

Production and variants

Production runs were undertaken between 1979 and 1985 by a consortium led by AEG and Krupp with electrical components from BBC and mechanical assemblies from Henschel. Sixty units entered service with fleet numbers 120 001–120 060. Several prototype and pre-production machines experimented with alternative cooling schemes and forced-ventilation systems developed alongside Siemens labs.

Variants included testbeds fitted with advanced power electronics later used on export models supplied to operators such as SBB CFF FFS and ÖBB. Some locomotives underwent mid-life upgrades to replace early semiconductor modules with insulated-gate bipolar transistors influenced by innovations at Infineon Technologies and industrial research at Fraunhofer IZM.

Service history

Upon introduction, units were allocated to major depots in Frankfurt am Main Hauptbahnhof, Hamburg Hauptbahnhof, and Mannheim Hauptbahnhof to take on express passenger duties previously handled by DB Class 103 and DB Class 111. Their entry coincided with timetable reforms influenced by planners from Deutsche Bundesbahn headquarters and the launch of intercity services connecting hubs such as Munich Hauptbahnhof and Berlin Hauptbahnhof.

Operational evaluations involved cooperation with research institutes including RWTH Aachen University for vibration analysis and with Karlsruhe Institute of Technology for traction performance. Over time, duties expanded to include fast regional expresses and charter workings for events at venues like Olympiastadion Berlin and Deutsche Oper Berlin.

Operations and deployment

The Bo′Bo′ configuration lent itself to mixed-traffic capability on electrified networks across Germany, with some locomotives tested on cross-border services to France and Switzerland under bilateral agreements involving SNCF and SBB CFF FFS. Deployment patterns shifted after the formation of Deutsche Bahn AG in the 1990s; several units received liveries and numbering updates to align with corporate branding overseen by DB Fernverkehr and depot allocations managed from regional centers such as DB Regio offices.

Maintenance regimes were standardized across depots in agreement with spare-parts suppliers including Siemens and ThyssenKrupp subsidiaries, and workshops adopted predictive maintenance methods influenced by pilot projects at Bundesbahn Central Office.

Preservation and legacy

A number of locomotives have been preserved by heritage groups including the DB Museum and private societies operating out of Neustadt (Weinstraße), where static exhibits and occasional mainline-certified examples appear at enthusiast events. The Class 120 legacy influenced families of European locomotives and EMU designs from Siemens EuroSprinter and Bombardier platforms, and continues to be cited in academic papers from TU Dresden and Universität Stuttgart on traction control and power electronics history.

Category:Railway locomotives introduced in 1979 Category:Electric locomotives of Germany