So what’s the point then?
From what I have seen of ERTMS, it relays to the driver the safe speed that he can be driving at any given moment. Rather than driving to 3 or 4 aspect signalling, his speedomete displays the safe maximum speed at anytime based on the proximity of the next train or occupied block ahead. And the beauty of this is that the display reacts in between signal blocks - giving the driver a chance to speed up - where under conventional signalling he would have to wait until he can visually see the signal before speeding up.
This in theory regulates the distance between trains better and improves capacity. ERTMS would be one qualifying factor for allowing speeds of greater than 125mph. Other factors such as increased energy use, increased wear on track and trains create extra cost and can only be justified if a reduction in journey times will increase revenue to cover those extra costs.
In the context of this thread, higher speeds have an impact on the train paths, so no point in saving a few minutes getting to York -for example - if you cannot get a path there that does not conflict with other trains.
Getting back to what's possible for December 2024, what do those 'in the know' believe is possible with regard to implementing the aspirational faster services between London and Edinburgh while fitting everyone else's rights and working around their timings? So what sort of timetable is possible?
Surely frequency and capacity are the drivers here. From my own experience trying to book a ticket (with a weeks notice) from Scotland to London was a nightmare because services were either full (no seats available) or ridiculously priced. Trying to get from Inverbess to Kings Cross, I actually was able to get a seat (well 2 seats) from Inverness to Edinburgh, but had to change and wait at Edinburgh because the 'Chieftain' could not offer me the same seats all the way through to the cross' . So that tells me more train services are needed.
Lumo seemed to ease the situation at first, but these are busy services now.
Should we be looking - and is it possible to think about every 20 minutes to Edinburgh - even at the expense of slightly slower journey times? After all greater frequency is a time saver in itself.