doi:10.3850/978-981-08-6396-8_P051

ABSTRACT

Pandrol Ltd., together with Singapore LTA, have developed a new version of the low stiffness VANGUARD rail fastener that can be easily retro-fitted in place of the existing Double FASTCLIP (DFC) in Singapore. The Pandrol VANGUARD system uses the principle of rubber in shear to support the running rail by the web and the underside of the railhead, rather than using a rubber support under the rail foot, When the VANGUARD system is installed, very low levels of vibration are transmitted into the ground in and around metro tunnels. The measurements in this trial show an insertion loss of approximately 6dB (VANGUARD versus DFC). This gives LTA a new fastening option to combat the problem of ground borne vibration in the critical low frequency range between 20Hz and 500Hz. A trial was conducted in September 2009 on the newly built Circle Line 2 (CCL2) where both VANGUARD and DFC were fitted into track and assessed. The trial involved taking recordings of rail deflection and concrete slab vibration under traffic for each fastener so that direct comparisons could be made. This paper describes the methods used for fitting fasteners and measuring both deflection and vibration. There is a discussion of the findings, including rail dynamic movement and vibration insertion loss. The circumstances where fitting VANGUARD to both existing and new-built track in Singapore may be advantageous are discussed.

Keywords: Fastener, Vibration, Insertion loss.

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