Toho Tenax, Kawasaki Heavy Industries to develop CFRP Springs for railcar trucks

Toho Tenax Co Ltd, the core company of the Teijin Group’s carbon fibres and composites business, has announced that it has agreed with Kawasaki Heavy Industries, Ltd. to jointly develop a carbon fibre reinforced plastic (CFRP) leaf spring that can be mass-produced for railcar trucks. The leaf spring was initially developed in 2013 and is already used in Kawasaki’s new-generation railcar truck, the efWING.

Toho Tenax will help establish an integrated system encompassing everything from the carbon fibre’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.

According to Teijin Group Executive Officer Takashi Yoshino, Teijin is accelerating its downstream strategy by leveraging its high-performance carbon fibre, with one such result being this joint development with Kawasaki Heavy Industries. Takashi is also general manager of the group’s Carbon Fibres & Composites Business Unit and president of Toho Tenax.

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.

The lighter materials and simplified design help to reduce the truck frame’s weight by some 900kg per railcar. Benefits include more efficient running costs and lower CO2 emissions, as well as the reduction in the risk of wheel derailment.