Heathrow Express staff will transfer to GWR▸ under TUPE▸ arrangements.
A smart move by First. Those Cl. 387's will be surplus once CrossRail starts so I would imagine the DfT» would have transferred the units to another operator. With this arrangement, GWR keep the units, the Heathrow Express will eventually cease to operate (who's going to want to travel on an express service from Heathrow to Padd only to have to change back onto a CrossRail service at Padd?). Once the Heathrow Express service ceases to run those 12 units could be reassigned to run Oxford stoppers once it is electrified, a Reading to Heathrow service once constructed or used on the North Downs. Not only would GWR benefit from keeping the surplus 387' but also inherit a number of qualified drivers.
I think it probably goes further than you suggest. The press release gives a heavy hint that the DfT will be 'progressing' the proposed western - to the
GWML▸ - and southern - to the South Western main line - routes from Terminal 5. The first of these goes to its final statutory public consultation in the next few weeks. If all goes well this means that the way is clear for construction to start and I suspect that the DfT will set up a special-purpose company - like
HS2▸ Ltd or East-West Rail Ltd - to push things along faster than Network Rail seems to be able to do. I would guess that the new connection could be ready in five or six years time - well before the end of the 10 year agreement mentioned in the press release. The link to the South Western may take a couple of years longer.
So HEx, far from ceasing, will evolve into a fast service from Paddington to Heathrow which will project to at least Reading and, using the 750v dc capability of the 387s, go through to Guildford and, possibly, Basingstoke. After all the press release states
This agreement, which confirms fast, non-stop rail connections for Heathrow passengers over the next decade,
. This makes sense, its operating costs will be reduced as the need for its own maintenance depot will disappear and the trains will use the shared facilities at Reading and it will attract a whole new market from the areas south west of Heathrow for easy connection to western London and Crossrail at Paddington and avoid the detour via Waterloo. Some Heathrow to central London passengers may switch to Crossrail but it will pick up a new source of passengers and revenue.
