Alta project makes existing diesel trains electric

Alta Battery Technology has made several technical advancements to its Battery Electric Tender (BET) system, demonstrating that practical, scalable rail decarbonisation is achievable with existing locomotive fleets.

The refinements, developed through work on the ARENA-funded project with Aurizon, position the BET as a commercially viable solution that can be deployed years ahead of fully electric alternatives.

Alta’s engineering team has optimised the BET’s design to deliver performance for Australian operating conditions, with the system now ready to move from concept to construction.

At the heart of the BET is a 2.3 MWh (previously 1.8) modular lithium battery system paired with five bidirectional 500 kW DC/DC converters, enabling controlled, high-efficiency power exchange between the battery system and the locomotive’s traction motors.

This distributed converter configuration supports traction drive, regenerative braking, idle charging from the diesel engine, and ground charging from external infrastructure.

“The multi-converter architecture is what sets this system apart,” said Roy Zou, Managing Director of Alta Battery Technology. “By distributing power across five converters operating in parallel, we achieve even power distribution and battery balancing that significantly reduces degradation.

“Each battery pack maintains optimal performance, and the system can scale as requirements grow.”

The 48-foot containerised BET can now extend a trip range — up to an extra 400 km — with charging infrastructure at each end, or operate in hybrid mode using diesel outbound and battery-electric on return journeys.

The company said the BET’s advanced Train Control System enables seamless coordination between battery-electric and diesel-electric operation. This transforms conventional diesel locomotives into dual-power platforms capable of autonomously managing power flow, regeneration and safety interlocks, capabilities typically found only in purpose-built next-generation electric locomotives.

Since commencing the project, Alta has refined how the system automatically manages traction power, regenerative braking and charging transitions with minimal driver intervention.

“As the diesel engine ramps up and down, we fill the missing portion with battery power, creating a completely seamless experience,” Zou said. “The driver operates the same controls they’re familiar with, with no operational disruption. They’re simply driving a more efficient, lower-emission locomotive.”

Alta’s technology addresses a critical challenge facing Australia's rail freight sector — how to decarbonise operations without waiting a decade for fully electric trains or maintaining dual systems indefinitely.

A BET can be constructed in approximately 12 months, providing a deployment timeline that’s up to 10 years faster than some other fully electric alternatives.

“We have proven it can be built and it’s ready for deployment,” Zou said. “These are optimisations we’ve validated through rigorous engineering work that directly addresses the realities of Australian climate and operational requirements.

“When battery-electric locomotives do become commercially viable, the BET’s electric architecture will integrate seamlessly with them, future-proofing today’s investment for decades of operation.”

Image supplied by Alta Battery Technology.