Project Profile: Siemens Desiro ML Cityjet eco Battery Train

The Siemens Desiro ML Cityjet eco is a pioneering electro-hybrid passenger train developed to decarbonize Austria’s non-electrified railway segments. This project retrofits existing Desiro ML electric multiple units (EMUs) with an advanced battery system, enabling zero-emission operation and providing a scalable solution for seamless travel across mixed-electrification networks. It represents a critical component of Austrian Federal Railways’ (ÖBB) strategy to achieve a fully carbon-neutral fleet.

Technical Specifications

The core innovation of the Desiro ML Cityjet eco is its electro-hybrid battery drive system, which allows the train to operate on both 15 kV AC electrified lines and non-electrified routes. The system utilizes three roof-mounted battery containers on the middle car, housing Lithium-Titanate-Oxide (LTO) cells with a total installed capacity of 528 kWh. This LTO technology was selected for its high durability, rapid charging capabilities, and a projected lifespan of 15 years. The batteries are charged directly from the overhead catenary while the train is on electrified sections, eliminating the need for dedicated charging infrastructure. The traction system delivers a maximum acceleration of 1 m/s² under catenary power and a robust 0.77 m/s² in battery mode. The design maintains a maximum axle load below 17 tonnes, even with the added weight of the battery packs, ensuring compatibility with existing infrastructure. The train complies with all relevant European safety standards, including TSI crashworthiness (EN 15227) and fire protection (CEN/TS 45545).

Key Takeaways

• Decarbonization of ‘Last Mile’ Routes: The project provides a viable, zero-emission alternative to diesel trains on non-electrified branch lines, reducing local air and noise pollution while eliminating an estimated 50% of CO2 emissions compared to diesel counterparts.
• Operational Flexibility and Efficiency: By enabling seamless transitions between electrified and non-electrified tracks, the battery-hybrid model eliminates the need for locomotive changes, reduces journey times, and optimizes fleet utilization across the entire network.
• Validation of Scalable Technology: The successful conversion of a standard EMU platform proves the technical and economic feasibility of retrofitting existing fleets with battery technology, offering a scalable pathway for other European operators to modernize their rolling stock and meet climate targets.

Frequently Asked Questions (FAQ)

What is the Siemens Cityjet eco train?

The Siemens Cityjet eco is an electro-hybrid passenger train used in Austria. It is an electric train equipped with a high-capacity battery system on its roof, which allows it to run on railway lines that do not have overhead power lines, providing a quiet, zero-emission alternative to diesel trains.

How does the Cityjet eco train charge its batteries?

The train charges its batteries automatically while operating on electrified sections of the railway network. It draws power from the overhead catenary lines to both power the train and recharge the onboard Lithium-Titanate battery system, meaning it does not require special stops or dedicated charging stations.