Since TFL planned to add additional Crossrail services to Heathrow serving Terminal 5, what does the future look like for Heathrow Express?
The 2tph that will serve T5 are likely to effectively be an express service, but with one additional call at Ealing Broadway (as well as continuing beyond Paddington). Though less frequent than the 4tph Heathrow Express, these 2tph will still have the same fares as the stopping services from T4, significantly cheaper than the express without booking far in advance.
The only real advantage left of the Express is the comfort of services - however this is aimed at business travellers, who are likely to prefer Crossrail as a direct link to the West End, the City or Canary Wharf.
Could we eventually see the Heathrow Express withdrawn in favour of an additional 4tph Elizabeth Line to T5 (by extending some of the Paddington-terminating services)?