In message , at
00:50:18 on Wed, 28 Sep 2005, Richard J.
remarked:
According to CULG, it closed on 28 May 1993 for conversion to 4-rail
operation, and reopened on 19 Jul 1993. I assume this was when the
ex-Southern Railway Class 487 were replaced by Class 482, aka 92ts.

They also did some work to the tunnel lining, but didn't fix
*everything* - there were still a couple of places where it was
uncomfortably close. This was all explained at their 100 year
exhibition.
--
Roland Perry