In message ,
writes

Space for the overhead line isn't the problem. Single deck trams are much
taller than tube trains.

There's quite a bit of clearance above the height of a tube train:

http://www.flickr.com/photos/richard...s/z/in/photost
ream/

In fact, at one stage BR class 503s from Merseyside were going to be
used on the line. Here's a rare picture of clearance trials:

http://www.gscalecentral.co.uk/f/dow...?file=1;127888

However, the length of the 503s proved to be a problem, as there is a
tight S-bend in the tunnel, hence the adoption of tube stock (plus, the
aluminium-bodied stock was much better able to cope with salt spray on
the pier).

If the tram proposal does go ahead (which I think is unlikely), it is
more likely to adopt street running, as the proposal for the Ryde Relief
Road would take traffic away from the Esplanade (which is currently the
main road through the town).

--
Paul Terry