Your article on the Changi Airport trackwork (NCE 13 September) was interesting and topical; however, a couple of corrections are needed.
The Pandrol Double Fastclip rail fastening system was specified, rather than agreed by the client. As you noted, it allows height adjustment to overcome the common slab track problem of matching new and worn rails during maintenance.
This height adjustment, together with the replacement of normally used embedded bolts by cast iron 'shoulders', to reduce the impact of corrosion, are the major advantages of the system.
The test site was installed by the TUS JV, trackwork contractor for the Singapore North-East Line, and instrumented by Pandrol.
Vibration measurements showed no deterioration in performance over the three month test period and, coincidentally, the measurements demonstrated the vibration mitigation effects of rail grinding, which was also undertaken.
David Mould, The Old Mill, Staplecross, East Sussex, TN32 5QB