Operational100%4Over 4RetrofitNanjing, CN

Introduction

Alta was commissioned to deliver traction control systems for a series of four diesel-to-electric shunter conversions undertaken by Nanjing Iron and Steel. While the first units were configured with lithium iron phosphate (LFP) battery systems, the NGD004 locomotive marked a shift to a supercapacitor-based configuration. The project demonstrated Alta’s flexibility in adapting its traction and control technology to different energy-storage architectures within a common platform.

Energy Storage Comparison: LFP vs LIC

LFP (Lithium Iron Phosphate) and LIC (Lithium-Ion Capacitor) systems each offer distinct advantages depending on operational needs:

  • LFP provides higher energy density and longer sustained output, ideal for continuous or long-distance operation.

  • LIC prioritises power density and rapid charge–discharge performance, making it well suited to short-haul, high-frequency shunting applications.

This project integrated both configurations across four locomotives, allowing Nanjing Iron and Steel to evaluate performance across multiple duty cycles within the same fleet.
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Nanjing Iron & Steel NGD004 Locomotive

Alta's Scope of Work

Alta supplied and integrated the following systems and components:

Technology Snapshot

The NGD004 locomotive operates on a 700 V, 200 kWh supercapacitor system paired with an 880 kW traction drive, providing rapid power delivery and high-cycle endurance for frequent start-stop operation.

NGD-004Battery SystemBattery ChemistryRated VoltageUsable CapacityAvailable System PowerRated PowerSupercapacitorDC 700 V110 Ah200 kWh1000 kW
NGD-004Traction SystemRated Input VoltageRated Output VoltageRated Input CurrentRated Output FrequencyRated PowerDC 700 VAC 380 V600 A50 Hz880 kW

Outcome & Significance

The NGD004 project reinforced Alta’s reputation for engineering adaptable traction platforms that can accommodate diverse energy technologies. By pairing established traction and control systems with a next-generation supercapacitor module, Alta provided Nanjing Iron and Steel with a highly responsive, low-maintenance powertrain optimised for high-frequency, short-range industrial use.