Nuremberg Automatic U-Bahn: A Case Study in Automated Railway Technology

This article explores the Nuremberg U-Bahn (underground/metro) system, focusing on its innovative transition to automated operation. The project, known as RUBIN (Realisierung einer automatisierten U-Bahn in Nürnberg), represents a significant milestone in railway technology, demonstrating the feasibility and benefits of converting existing manual metro lines to driverless operation while maintaining service continuity. The analysis will delve into the project’s phases, technological advancements, operational strategies, and overall impact, highlighting its potential for global replication. The aims of this study are to analyze the technical challenges overcome during the RUBIN project, assess the economic and operational benefits of automation, and evaluate the scalability of the Nuremberg model for other urban rail systems worldwide. We will examine the specifics of the rolling stock, infrastructure modifications, signaling and communication systems, and the long-term implications of this successful automation project.

Rolling Stock and Infrastructure Enhancements

The Nuremberg U-Bahn operates with three classes of rolling stock (DT1-DT3). The DT3 class, specifically designed for automated operation, was built by Siemens in Vienna. These trains, featuring through-gangways for improved passenger flow and security, lack traditional driver cabs, offering unobstructed passenger views and manually operable controls concealed in lockable units for emergency situations. Automatic extending flaps facilitate accessibility for wheelchair users and strollers. The trains are designed to accommodate bicycles and feature a large general-purpose area. The infrastructure includes mostly subsurface lines, with some open sections on U1. The U1 and U2/U3 lines intersect twice near the Hauptbahnhof (main station), a key transport hub. Most tracks are unballasted and utilize island platforms standardized to train lengths. U11 and U21 designations on maps indicate shorter runs on U1 and U2, not separate lines. The U3 line largely shares tracks with U2 between Rathenauplatz and Rothenburger Strasse, branching out to Maxfeld and Gustav Adolf Strasse. The design prioritizes accessibility, with lifts at all stations.

Signalling, Communication, and Operational Strategies

A notable aspect of the Nuremberg U-Bahn is its mixed operation of both automated and manually driven trains on the same tracks. This necessitated a sophisticated Automatic Train Control (ATC) system from Siemens, capable of managing both modes. Unlike many automated systems, platform edge doors were not implemented due to potential disruptions and alignment challenges with manually operated trains. A robust track obstruction detection system interlocks with the ATC for emergency stops and alerts the control center, which also benefits from CCTV coverage. Trains are equipped with CCTV and audio intercom for communication with the control center. Ticketing integrates with the broader German system and the VGN tariff union, also encompassing Deutsche Bahn (DB) Bayern tickets. The move towards driverless operation was driven by cost reduction, the opportunity to modernize rolling stock, and the ability to adjust service frequency dynamically based on demand. The goal was to increase the frequency of services, especially on the core section of the U2 and U3 lines. The precise operation of automatic trains enabled higher frequency services.

Project Overview and Timeline

The RUBIN project, initiated in 1997, involved a feasibility study by VAG (Verkehrs-Aktiengesellschaft Nürnberg – Nuremberg Transport Company), Siemens, and Adtranz (later Bombardier). Construction of the U3 line, Germany’s first automatic metro line, began in 2003, experiencing some delays related to the ATC system. Public service commenced in June 2008, making it the first system globally to operate both automatic and manually driven trains on shared tracks. The U2 line was fully converted to automatic operation by September 2009. Further extensions were planned, including the completion of the U3 line beyond Maxfeld by 2011 and additional stations by 2013, along with a southern extension towards Fürth. However, a planned U1 extension was postponed due to anticipated developments in the target area not materializing.

Project Summary

Conclusions

The Nuremberg RUBIN project stands as a remarkable achievement in automated railway technology. Its success demonstrates the practicality of converting existing metro systems to driverless operation, offering significant operational and economic benefits. The seamless integration of automated and manually driven trains on the same lines showcases a level of technological sophistication and system integration rarely seen in earlier projects. The meticulous planning and execution, while facing some initial delays, resulted in a system that improves efficiency, passenger experience, and accessibility. The choice to prioritize accessibility through features like automatic extending flaps and lifts at all stations showcases a commitment to inclusive design. The strategic decisions made during the project highlight the importance of considering both immediate and long-term goals. The project’s impact extends beyond Nuremberg, providing a valuable model for other cities considering automated railway solutions. The RUBIN project’s success underscores the viability of converting existing manual systems into modern, efficient, and cost-effective automated systems. This achievement opens up new opportunities for urban rail systems globally, promoting sustainable transportation and enhanced passenger service. This case study offers valuable insights into the practical implementation, operational strategies, and long-term implications of such a significant upgrade to an existing urban railway network. The careful integration of new technology into an existing system, while maintaining service continuity, provides a blueprint for future urban rail modernization initiatives worldwide.

Company Information:

VAG (Verkehrs-Aktiengesellschaft Nürnberg): Nuremberg’s public transport operator.
Siemens: A global technology company with significant involvement in railway systems, including signaling, rolling stock, and automation technologies.
Adtranz (later Bombardier Transportation): A major player in the rail industry, now part of Bombardier Transportation. (Bombardier Transportation is now Alstom).
Deutsche Bahn (DB): Germany’s national railway company.