"Cast_Iron" wrote in message ...
Tube stock and surface stock are approximately the same width, it is only

Not true , surface stock is a foot wider which amounts to a lot more extra
room inside the carriages.

Of course situations change and hindsight is a wonderful thing. I am however

You don't need hindsight to know that bigger trains = better carrying
capacity.

quite sure that if it had been decided to build the Heathrow extension to
surface stock loading gauge the whingers would have been complaining about
the additional expenditure and little use.

Even if the picc continued running the main service to the airport some
distruct trains could have used it occasionally to take up the slack, the
same way that the picc and met run togather to uxbridge.

B2003