Indian Railways Case Study - Trelleborg IAVS - Trelleborg AB

Trelleborg sandwich mounts offer significantly improved service life in India's WAG7 freight locos

Indian Railways makes the Trelleborg rectangular bearer spring the secondary suspension of choice due to exceptionally long service life.


Originally selected in the mid 1970s, the Metalastik rectangular bearer springs achieved a life of six years despite the forces exerted by tight turns on the track. A subsequent change to locally-manufactured parts resulted in a reduction to just nine months in service and so Indian Railways returned to the original Trelleborg product in 2000. Since then the company has supplied over 17,000 units and the service interval is back at six years once again.


Rod Holroyd, Global Market Manager for Rail, at Trelleborg Industrial AVS, commented: “We are very proud of our long-standing technical collaboration with Indian Railways. The quality of the Metalastik product and its engineering has created a lasting solution for a very demanding application and, by working closely with the customer's engineers we have been able to further increase the product’s performance."

The Metalastik® rectangular bearer spring is a robust rubber/metal laminated sandwich mount, fitted to the locomotive bogie to absorb high levels of noise and vibration.  They are designed to allow bogie rotation, track twist and lateral displacement. In a revised geometry some designs can also be used as traction centres. The bearer srpings have been used in both new-build locomotives, and retrofit replacements in the refurbishment of older freight locomotives.

WAG-7 is a Co-Co electric locomotive with a maximum operating speed of 100 kph.  Indian Railways’ Chittaranjan Locomotive Works (CLW), one of the leading manufacturers of electric locos in the ASEA region, is responsible for both the mechanical and electrical build of the locomotive and some 300 have entered service since 1992.



Rectangular bearer springs

Rectangular bearer springs are designed to support the vehicle body in their compression mode whilst allowing horizontal, lateral and rotational bogie movements by virtue of the more flexible shear mode.