Trelleborg's suspension components chosen again for Jubilee Line

The original suspension components, which have been giving reliable service since they were supplied by the company in 1995, are now undergoing a comprehensive overhaul under the new contract. Trelleborg's Metalastik chevrons act as the primary suspension, and Hourglass springs as the secondary suspension. Trelleborg is also supplying the centre pivot bushes, together with auxiliary bogie components.

Metalastik chevrons are fitted in pairs at the axle box to provide longitudinal, vertical and lateral flexibility and are designed to absorb high levels of shock and vibration. They are made from a special low-creep rubber compound, which established new standards on the London Underground when first installed.

The other major component of the Trelleborg suspension package is the Hourglass bearer springs, which are mounted in pairs, on the bogie. They consist of two hemispheres of rubber bonded to top, bottom and central steel plates, to provide a rising stiffness characteristic which reduces height variation between empty and fully laden carriage weights. They accommodate horizontal and torsional displacements, with vertical frequencies of 1.8 to 2.5Hz, and offer high-quality ride performance combined with simplicity, long service life and low maintenance.

Since the first fleet of 59 six-car trainsets was built by ALSTOM, four new seven-car trainsets and 59 trailer cars have been added to the fleet so that all trainsets are now in a seven-car format, allowing the extended trains to carry an additional 180 passengers.

To find out more about Metalastik components from Trelleborg Industrial AVS, please visit their website at www.trelleborg.com/industrialavs/.