Updating existing rail vehicles with a modernized drivetrain helps to improve fleet efficiency while keeping costs and service interruptions down. This approach is known as “repowering”. At this year’s InnoTrans, the international trade show for transport technology, ZF and Irish Rail signed a Memorandum of Understanding about a potential new repowering project starting in 2025. The partnership revolves around ZF’s new EcoWorld 2 six-speed powershift transmission, which decreases fuel consumption, improves ride comfort and reduces maintenance efforts.

No surprise: train passengers want their rides to be on time, safe and comfortable, while rail operators aim for the highest possible degree of reliability and efficiency. Part of this equation is keeping the fleet up to date. However, ordering brand new vehicles is often not the most economical or ecological way to do so. Luckily, ZF has the solution: repowering, that is, retrofitting existing rail vehicles with modern transmissions. “With repowering, we offer our customers all the drive benefits of new vehicles, while keeping costs and service interruptions down,” explains Stephen Brew, key account manager for Rail Drive Systems at ZF.

While the most obvious advantage of repowering is to prolong the service life of older vehicles, it provides an even greater return on investment for newer models too. “Consider how significant the fuel savings can be,” states Brew. “The earlier you update the driveline, and make it more efficient, the more those savings compound – not to mention the reduced amount of carbon emitted into the environment.”

A new addition to the company’s repowering portfolio, highlighted at this year’s InnoTrans in Berlin, is the EcoWorld 2 powershift transmission for diesel multiple units (DMUs). The system has already led to an exciting new project.

New repowering project: ZF and Irish Rail to extend partnership

At this year’s InnoTrans in Berlin, ZF and Irish Rail have signed a Memorandum of Understanding about a potential new EcoWorld 2 repowering project. ZF had already helped to retrofit power packs (i.e., engine and transmission as a combined unit) for Ireland’s national railway network operator back in 2018 – at that point with the EcoWorld 2’s predecessor. “After experiencing the improved performance and reliability of ZF’s modern driveline technology, we were very interested in extending the collaboration,” comments Jim Meade, CEO of Irish Rail.

“The partnership has provided valuable experience for both companies. We appreciate the trust that Irish Rail has extended to us, and which we will continue to build upon with the quality that ZF is known for,” adds Brew.

Beginning in September 2020, Irish Rail launched an extended durability of the EcoWorld 2 test of a newly repowered three-car DMU. Still ongoing, the trial train has covered over 650.000km so far. The transmission excelled with utmost reliability and proven fuel consumption reductions by up to 20 percent. Both parties agree that these results are a compelling reason to consider a large-scale fleet repowering. If successfully evaluated and sanctioned by the government stakeholders, the project could begin in 2025 and see ZF delivering more than 230 EcoWorld 2 transmissions over a period of three years.

EcoWorld 2: Systemic improvements for powerful performance

An update to the established model series, the six-speed EcoWorld 2 decreases fuel consumption and CO2 emissions, in some cases 20 percent and more, while at the same time providing better acceleration. Its weight distribution has been revised, as has its new Transmission Control Unit (TCU). Thanks to its integrated retarder, the EcoWorld 2 also puts less stress and wear on the brake system, keeping maintenance efforts low. This also improves its noise characteristics while decelerating. With a specialized gear design, the engine runs at fewer revolutions per minute even at full speed, which keeps the noise further down, to the comfort of both passengers and residents near the tracks. It produces much lower heat, translating to less wear on the hydrostatic and other parts of the cooling system, which again reduces maintenance effort.

These advantages, plus its ability to handle torque from powerful modern diesel engines, make the EcoWorld 2 the ideal choice for DMUs completing arduous routes and heavy-duty cycles. This includes high-speed stretches, climbs and commuter routes with high passenger counts and multiple stops along the way.

Repowering with EcoWorld 2

EcoWorld 2 can be retrofitted either in a power pack or mounted separately from the main engine connected via driveshaft. For this set-up, ZF developed a special transmission housing and flywheel cover known as “EcoBell”, which allows installation in even more vehicle platforms.

Through its Aftermarket Division, ZF can supply everything from single hardware components and transmissions to complete solutions including technical support. As Brew sums up: “It’s all about meeting the customer’s needs.”

ZF is able to offer different levels of integration to accommodate the respective vehicle’s specialized internal communications network. In the case of EcoWorld 2, its integrated Electronic Control Unit (ECU) and TCU support a full CAN system, while a separate Input/Output box can process discrete analogue and discrete digital signals, e.g. in a partial CAN setup.

The EcoWorld 2 is also ‘stop-start’ and hybrid-ready, therefore well-suited to help operators meet climate goals. Plus, they can be combined with ZF’s “connect@rail” condition monitoring system to support predictive maintenance scheduling. 

zf.com