Dr Zarkoff Wrote:
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> Corrugated railhead is a side effect of running
> resilient wheels on rigid track. In the early
> 1950s, the tracks on Market St were done, laying
> the rail on large concrete pads. By the 1960s and
> 1970s, the PCCs super resilient wheels had
> corrugated the rail pretty severely (the Muni
> stopped running the grinder in the late 1950s).
> These tracks were ripped out and relayed during
> the BARTD construction. BATRD itself uses a
> resilient wheel and rigid track in the subways and
> elevateds, so these areas are prone to corrugation
> too. BARTD actually does have a grinding program
> because in certain areas, the elevateds and
> subways are quieter than they were a couple of
> years ago.

So why run resilient wheels? With modern sound insulation I would think noise from wheels inside the carbody would be a non issue.