No trains into the CTA at Heathrow…
 

Will update more as I know.

Twitter goss said something about a helium balloon in the Elizabeth Line tunnel, but doesn't explain all trains, as now reported

A foil helium balloon is wrapped around the overhead cable at the entrance to the tunnel. All trains suspended at the moment.

Is it from our friends in China wanting to check on us?!

Yes definitely an overhead line (catenary) issue as others have said as I can see that as the attributed reason for one of the impacted trains. For those that wish to see the real-time situation of trains on the ground then the Signalling Diagram will help.

EDIT - I should add that this will impact all trains to/from Heathrow, i.e. CrossRail/Elizabeth Line and Heathrow Express to all terminals.

Drat. Was hoping for a nice quiet tube trip to T5 today. Now it'll be rammed. Disruption between Paddington and Heathrow trains expected until end of day.

For future reference, can someone explain what CTA stands for please?

central terminal area, so the bit in the middle of the airport where T2 and T3 are.

The joint HEX/crossrail station in the central area is called Heathrow Central.

the tube is running fine as well in case anyone needs alternatives.

Yep, not too busy.

Just to update for those travelling this afternoon that things look to be back to normal, but always worth checking before you head for the station.

If you are on Crossrail / at Paddington when this happens it isn't a bad back up to head to Hayes & Harlington instead. There are various bus options or you can get an Uber. Though there is a really weird situation that I couldn't quite understand if they stop on what seemed to me to be a drop off zone outside the station a permanently stationed "warden" takes their photo and they get a ticket! So help out your driver and have them pick you up somewhere on the main road

Yes useful advice - if you mean station approach, that is a no stopping zone with £100 charge. The main road is also double yellows/bus stops so care needed. Have had similar when grabbing an Uber at Ealing Broadway - need to walk a little to somewhere your driver can pull in.

Just noting that Hayes and Harlington is the last Crossrail stop before they turn off the main line to Heathrow, so you just "get off" there rather than "head there instead".

When there is disruption in the Heathrow tunnels, they often terminate short at Hayes & Harlington anyway, as quite a number have done today.

Important to distinguish between “the CTA” and CTA:

The former: the Central Terminal Area at LHR

The latter: an airport in Sicily, a BA destination in its own right, otherwise known as Catania, to which it is unlikely there will be direct trains from London unless this is ever built:

https:/en.m.wikipedia.org/wiki/Strait_of_Messina_Bridge

Also the CTA, in respect of the U.K. is the Common Travel Area - The British Isles. That’s what I initially thought when I read the thread title - as I’ve never heard of the Central Terminal Area as I’ve always heard it just referred as the Central Area. Thought it was a bit odd until I read on!!