David Howdon wrote:
There were delays on the Piccadilly line tonight but I found the station
announcement at Acton Town most odd. Here is what it said (almost an
exact quote)

"Due to a signal failure at Hangar Lane - Rayners Lane and Uxbridge
trains will be terminating at Northfields".

Can anybody explain how
a) a signal failure on the Central Line can cause delays on the
Piccadilly Line?

There are places on railways that are not stations. Just because there
is no *station* on the Piccadilly Line called Hanger Lane (and let's
get into another discussion on why there isn't one), it doesn't mean
that there isn't a signalbox/junction/crossover/signal/depot/siding
or whatever at that location.

The Central and Piccadilly Lines cross near Hanger Lane / Park Royal.
It's not inconceivable that there is a signal on the Piccadilly Line
called "Hanger Lane".

b) How trains to Rayners Lane and Uxbridge which do not go through
Northfields can possibly terminate there?

They mean that trains from Central London which should have gone on the
Uxbridge Branch to Rayner's Lane, have been diverted to go onto
the Heathrow branch instead; to avoid congestion nearer to Heathrow,
they are terminating at Northfields.

This presumably all means that there are no trains between Acton Town
and Rayner's Lane.

Richard [in PE12]