ZF Launches EcoFlex Low-Maintenance Fiber Composite Coupling for Electric Rail Drivelines Ahead of InnoTrans 2026 Premiere

Strong flex: ZF launches EcoFlex, a low-maintenance coupling for electric rail drivelines

(IN BRIEF) ZF is launching EcoFlex, a new lubrication-free fiber composite coupling for electric multiple units and metro vehicles, designed to improve fleet availability while reducing maintenance and lifecycle costs. Installed between the traction motor and gearbox, EcoFlex combines torque transmission, damping and electrical insulation in a single component. Its fiber packages are embedded within an elastomer element that helps absorb dynamic movement while providing electrical resistance exceeding 1,000 MΩ, eliminating the need for additional insulation measures in some applications. The current version can transmit up to 2,100 Nm and operate at speeds of up to 6,000 rpm, with replacement of the flexible disc assembly planned after approximately eight years depending on the application. EcoFlex can be adapted for both new vehicles and retrofit projects and is intended to support improved reliability, ride comfort and lower service requirements. Following successful validation tests, ZF is preparing metro field trials with a vehicle manufacturer and is developing additional coupling sizes. EcoFlex will make its public debut at InnoTrans 2026 in Berlin.

(PRESS RELEASE) FRIEDRICHSHAFEN/ BERLIN, 15-Sep-2026 — /EuropaWire/ — ZF is expanding its rail technology portfolio with EcoFlex, a newly developed fiber composite coupling for electric multiple units designed to reduce maintenance requirements while integrating torque transmission, damping and electrical insulation within a single component.

Installed between the traction motor and gearbox, EcoFlex has been developed for electric multiple units and metro vehicles where fleet availability, lifecycle costs, reliability and passenger comfort are increasingly important operational considerations.

ZF will present EcoFlex publicly for the first time at InnoTrans 2026 in Berlin, where the company will exhibit in Hall 20, Booth 580, from 22 to 25 September.

Rail operators are placing greater emphasis on drivetrain durability as electrified services expand and rolling stock utilisation increases. ZF notes that around 90% of rail traffic in Germany is already electrically powered, while heavily used rail corridors and metropolitan networks are placing growing demands on vehicle drivetrains.

For operators, unplanned workshop visits reduce fleet availability, while manufacturers must account for maintenance requirements when assessing lifecycle costs and vehicle competitiveness. ZF developed EcoFlex to address these demands with a lubrication-free architecture intended to minimise service requirements.

At the centre of the system is a flexible composite disc coupling incorporating circumferentially arranged fiber packages embedded in an elastomer element. The fiber bundles transmit torque while compensating for dynamic movement between the traction motor and gearbox.

The elastomer protects the fibers while also supporting rail-sector fire and smoke requirements. Its insulating properties, combined with the fiber structure, provide an electrical resistance of more than 1,000 MΩ, allowing EcoFlex to provide inherent electrical insulation without additional insulation measures normally required with some conventional coupling designs.

In its current configuration, EcoFlex can transmit torque of up to 2,100 Nm and operate at motor speeds of up to 6,000 rpm. ZF plans to develop additional coupling sizes with corresponding performance characteristics to expand the technology to a broader range of rail vehicles.

Unlike conventional lubricated curved-tooth gear couplings, EcoFlex does not require lubrication, reducing maintenance work associated with wear and lubricant servicing.

Routine visual inspections remain part of the maintenance programme, while ZF expects replacement of the flexible disc assembly after approximately eight years, depending on the validated duty cycle and individual application.

The simplified architecture is also intended to lower lifecycle costs through a reduced number of individual components.

EcoFlex provides integrated damping in addition to torque transmission. The interaction between the fiber packages, elastomer and integrated slipping bush helps limit torque peaks and dynamic load changes within the driveline.

By reducing these loads, the coupling can help protect surrounding drivetrain components while contributing to smoother vehicle operation and improved passenger ride comfort.

ZF has designed EcoFlex for flexible integration across both new-build and existing rail vehicles. Shaft interfaces and installation dimensions can be adapted to individual customer requirements, allowing the coupling to be incorporated into new EMU and metro platforms as well as retrofit programmes.

This retrofit capability is intended to give operators the option of replacing conventional couplings in existing fleets with a lower-maintenance alternative without requiring an entirely new drivetrain architecture.

Hans-Peter Niedermeier, Head of Product Development for Rail Drive Systems at ZF, said EcoFlex demonstrates how the company is expanding its rail portfolio around practical customer requirements.

He said the combination of lubrication-free operation, integrated electrical insulation and damping within one coupling can help operators improve vehicle reliability and comfort while reducing lifecycle expenditure, while also providing manufacturers with greater flexibility when integrating driveline systems.

Following successful validation testing, ZF is preparing the next stage of the EcoFlex development programme.

The company is currently in discussions with a vehicle manufacturer regarding joint metro field trials, which would evaluate the coupling under real-world operating conditions and provide additional information ahead of future series applications.

ZF is also carrying out pre-development work on additional EcoFlex sizes to address a wider range of vehicle types and drivetrain requirements.

EcoFlex will be unveiled during the ZF InnoForum on 22 September at 3 p.m., the opening day of InnoTrans 2026. The coupling will also be one of the principal exhibits at ZF’s stand, alongside the company’s broader portfolio of rail drivetrain technologies, chassis components, digital condition-monitoring solutions and global service offerings. 

About ZF
ZF is a global technology company supplying advanced mobility products and systems for passenger cars, commercial vehicles and industrial technology. Its comprehensive product range is primarily aimed at vehicle manufacturers, mobility providers and start-up companies in the fields of transportation and mobility. ZF electrifies a wide range of vehicle types. With its products, the company contributes to reducing emissions, protecting the climate as well as enhancing safe mobility. Alongside the automotive sector – passenger cars and commercial vehicles – ZF also serves market segments such as construction and agricultural machinery, wind power, marine propulsion, rail drives and test systems.

With some 153,000 employees worldwide, ZF reported sales of €38.8 billion in fiscal 2025.
The company operates 162 production locations in 29 countries.
For further press information and photos, please visit: www.zf.com

About ZF’s Industrial Technology Division
In the Industrial Technology Division, ZF pools its activities for off-road applications. Apart from the development and production of conventional axles and drive systems for a broad range of applications, the focus is on electrified or hybrid solutions as well as digital products and services that will help to make off-road mobility even more sustainable, safe, smart and reliable in the future. The division’s diverse product portfolio includes solutions for agricultural and construction machinery as well as for forklifts, special vehicles and rail. Additionally, the Industrial Technology Division oversees the global business involving marine propulsion systems, industrial drives and micro mobility solutions. The portfolio also includes test systems for a wide variety of applications in driveline and chassis technology. Furthermore, the division manages the activities of the ZF Group in the field of wind power technology. Around 25 percent of geared wind turbines installed worldwide are driven by ZF technology and supply more than 160 million households around the world with renewable energy.

Media Contacts:

Gernot Hein
Head of Communication & Public Affairs / Press Spokesperson, Industrial Technology Division
+49 851 494-2480
gernot.hein@zf.com

Svenja Mayer
Head of Marketing and Communications, Marine & Special Driveline
+49 7541 77-2418
svenja.mayer@zf.com

SOURCE: ZF