According to a December 22 press release from Teijin, Toho Tenax Co., Ltd., the core company of the Teijin Group’s carbon fibers and composites business, will work with Kawasaki Heavy Industries, Ltd. to develop a carbon fiber-reinforced plastic (CFRP) leaf spring that can be mass-produced for railcar trucks.

“Teijin Group is accelerating its downstream strategy by leveraging its high-performance carbon fiber, with one such result being this joint development with Kawasaki Heavy Industries,” said Teijin Group Executive Officer Takashi Yoshino, who is also general manager of the group’s carbon fibers & composites business unit and president of Toho Tenax. “Teijin Group aims to expand its carbon fiber and composite businesses by increasingly focusing on innovative transportation solutions, a key element focus of our downstream strategy.”

The leaf spring was originally created in 2013 and is already used in Kawasaki’s new-generation railcar truck, the efWING, which won the Good Design Gold Award in 2013 from the Japan Institute of Design Promotion. According to Kawasaki, the efWING benefits from CFRP in a number of ways, including 40 percent weight saving (up to 900 kg), lower CO2 emissions, lower maintenance over 40 years, and increased safety (including lower risk of wheel derailment).

Conventional railcar trucks use side frames and independent coil springs made of steel, but the efWING is the world’s first to combine these components in a simplified solution made of CFRP. For the railcar trucks, Toho Tenax says it will help establish an integrated system encompassing everything from the carbon fiber’s original yarn to the actual CFRP leaf springs. The new mass-production system will enable the efWING to be marketed on a global scale.