IMHO track access applications are usually considered more authoritative than PR stuff at launch. Which is the more recent?
I have no opinion either way about loco hauled trains, just quoting the words used in the TAA.
I would go off their website. Which company in their right mind would put out a public statement where the normal Joe Public would likely see it and not like us geeks on here ( I'm proud to be a geek) would go hunting around on the internet for conflicting rumours. Its like a motor company saying its next model is going to have 6 gears but when it comes out it only has 5 gears or something on that line. It would be PR suicide.
I noted people on hear saying 125mph would be overkill as the majority of the track at the moment is under 100mph. But it is for the track where you can get 125mph to increase capacity.
Look at the 350's and the retro fitting to 110mph so that capacity can be increased on the West Coast.
The following extract is from the DfT website:
First Trans Pennine Express Limited will operate services on the TransPennine Express franchise — which runs intercity services across the region and into Scotland — from April 2016 until March 2023. They
will bring in 220 new carriages, equivalent to 44 trains and worth more than £400 million, providing fast 125 mph services across the network, as well as:
I've highlighted the word "will", This means they have to be 125mph otherwise some one could get in trouble with the law. Part of my work in the past has been to write risk assessment/method statements and you have to be very careful in your choice of words. If you use words or phrases like will/have to these are an order and have to be carried out. If you use words like may/could its a request and not an order. So all should be 125mph unless someone wants to get into trouble with the law.