Actually the service introduced in May 1971 with two 1960s Class 27 locos and six Mk2 coaches had a timetabled nonstop time from Haymarket to Queen Street of 39 minutes (43 from Waverley). So the £2bn has slashed all of two minutes off what was achieved every hour nearly 50 years ago. Actually not even that; if the train was punctual it couldn't do any better because it came in on the heels of a stopping dmu, but if it left Edinburgh a couple of minutes late you would likely hit 100 mph (locos officially 90 mph limit) and get there in 37 minutes. I was a regular on this. Nowadays I'm dismayed that the stoppers and the express have just been merged into one slower service - and worse, often done with just a 3-car unit, and standing passengers even off peak.
Off topic, but a note in defence of the current Edinburgh-Glasgow shuttle compared with the push pull era.
I commuted daily on it for around eight years from the mid 2000s. Like you, I grumbled that it's slower now then it was when I first used it in the late 1980s and the push pulls, by then extremely unreliably operated by clapped out 47/7s that had been thrashed back and fore for a decade. Maybe the 27s were better on that front, but over time I doubt if they took any better to that sort of treatment.
Both then and now the route saw or sees a departure every 15 minutes in both directions. Then the express service, leaving on the hour and half hour, stopped only at Haymarket and Falkirk High. The stopper - an equally unreliable dmu, I had one that managed three inches down the platform at Waverley before it failed - went all stations via Grahamston and each one was overtaken by the following push pull.
Now all four per hour go via High. Those on the hour and half hour stop additionally at Croy, providing an excellent park and ride service to Edinburgh for that part of North Lanarkshire. Those at 15 and 45 stop at Linlithgow and Polmont, opening up expresses to Glasgow from West Lothian and the eastern Falkirk area. Grahamston and points north are well covered by other services.
It took me a while to twig this and cheer up as an end to end user, but a slightly slower turn up and go service that runs every 15 minutes is actually a bit quicker than a 42 or so minute one if you allow for the time spent waiting for the thing to depart from either end!
The mk3 push pulls were much nicer to travel in but were hopelessly unreliable towards the end due to locomotive faults. I think that in eight years of daily commuting on 170s the train itself was the cause of delay or cancellation only about a dozen times.
My point about EGIP costs wasn't at all serious. If we can get 37 minute end to end times with something close to the current stopping pattern, and the present overcrowding is massively reduced, then the route will be providing a great service.
