Michael Bell writes
There are shielded 3rd rails on the continent, but I'm afraid I
can't see Network Rail, with its many problems, and its difficulties
with the TOCs, undertaking a project like this, no matter how
worthwhile.

Protected third rail is used on the DLR. HSE would not allow any new
rail system to use unprotected third rail - although they will allow
extensions to existing systems.

From 1916 until around 1990, the Manchester Victoria-Bury service used
trains operating off a 1200V DC protected third rail - with a
side-contact. This system was replaced by overhead wires when the route
was converted for use as part of the Metrolink system.

A couple of pics which may help to illustrate the Bury system;
http://www.therailwaycentre.com/EMU%...le/504_asbuilt
http://easyweb.easynet.co.uk/~gsgleaves/gauge.jpg

--
Dave