In article ,
NY wrote:
I'm not sure why a north-to-west facing curve was never built between the
Heathrow spur and the GWML, to allow trains from Reading, Oxford, Bristol
and south Wales to reach Heathrow - even if it involved a change to a
Reading-Heathrow shuttle.

Because the line is at capacity from Newbury to Paddington.

So which services through Reading are you going to divert to
Heathrow? They have to be fast trains, otherwise it'll be quicker
to go to non-stop Paddington and change there.

What is the number of now inconvienced passengers (that wanted
Paddington and now have to change at Reading and stand if they can
squeeze on in the peak) v the number of passengers who have a better
journey?

Note that the service pattern from Reading - Heathrow needs to be
at least every 20 minutes to ensure that there are no passengers
who get a faster journey by travelling Reading - Paddington -
HEX, so you're going to have to divert a pretty large proportion
of the Reading to Paddington fasts; I'm not sure how many there
are, but losing 3tph would be very noticable.

--
Mike Bristow