In article ,
Piccadilly Pilot wrote:

The sub-surface lines can accomodate main line gauge stock although it does
get a bit tight in places with modern stock. In 1982 a test run was carried
out with two battery locos and a BR Mk2 coach. It got round the Circle
although it did touch in a couple of places. This was in preparation for
passenger workings using ex-Met loco No12 Sarah Siddons. In the event these
workings were limited to the Met Main to Amersham and Uxbridge. Sorry can't
be certain where the southern reversal point was, but I think Wembley Park.

ISTR it was first done (in recent times anyway) with the BR Track
Testing Coach when it was hired by LU, and it was the success of that
that led to the idea of railtours. That was the public version anyway !
One such tour was the Battery Rover, which took battery locos along the
Met and District parts of the Circle with a train of Mk2 aircons.

Nick
--
"And we will be restoring normality just as soon as we are sure what is
neurotypical anyway. Thank you". -- not quite DNA