Introduction

Alta’s Nanjing Metro Hybrid Electric Locomotive Shunter project represents a major step forward in sustainable rail transport. In 2022, Alta was commissioned to design the traction system, battery system, and electrical auxiliary components for a hybrid shunter. Set to be delivered by the end of 2024, this project aims to provide a cleaner, more efficient way to move train carriages and rolling stock around railway yards, depots, and stations.


About Nanjing Metro

Nanjing Metro is one of China’s leading urban rail operators, central to the city’s public transport. With a focus on improving operational efficiency and reducing its environmental impact, the introduction of a hybrid electric shunter aligns perfectly with their sustainability goals.


Advantages of the Hybrid Electric Shunter

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Nanjing Metro Hybrid Shunter

Enhanced Efficiency

This hybrid shunter incorporates a smart energy management system that optimises battery use alongside traditional diesel power. By cutting fuel consumption, it drives down operating costs and increases overall efficiency.

Battery System

The locomotive features an LTO battery system with a rated voltage of 745.92VDC and a capacity of 268Ah, delivering 200kWh of power. It’s built for power surges too, offering a peak output of 600kW for short bursts. The battery management system ensures stable performance and maximises battery life​

Environmental Impact

The hybrid electric setup slashes the shunter’s emissions, contributing to Nanjing Metro’s sustainability objectives. By relying on battery power for much of its operations, the locomotive delivers cleaner, greener transport

Auxiliary Power Components

Supporting the battery is a 300kW auxiliary battery charger, with an input of 3AC400V and an output of DC739.2V. This system recovers energy during braking, reducing fuel use and extending the battery’s lifespan​. Other key systems, like the 15kVA air compressor inverter module and 50kVA life power supply module, keep everything running smoothly

Operational Flexibility

This shunter is built to integrate seamlessly into Nanjing Metro’s existing infrastructure. Alta’s modular approach allows it to operate in diesel, hybrid, or pure electric modes, depending on the job at hand.

Challenges & Solutions

Alta has worked to overcome the challenge of integrating hybrid technology into an existing rail system by developing a PWM rectifier module, which allows the locomotive to switch between energy modes without compromising on performance​. Continuous collaboration with Nanjing Metro ensures the shunter meets the city’s unique operational demands.


Future Implications

The Nanjing Metro Hybrid Electric Shunter is paving the way for a new era of sustainable rail transport. By blending hybrid technology with proven engineering, Alta is helping reduce carbon footprints while maintaining reliable and cost-effective operations. This project sets the stage for future partnerships and innovations in rail transport across the globe.