This from Ithuriel...
The Invitations to Tender for the new replacement franchises, sees bidders get brownie points for quality improvements.
One good way to improve quality is to promise new trains, which generates points and, of course, points mean prizes!
But, new trains cost more money.
And the word on the tracks is that DfT is facing the prospect of all the bids for Thameslink Southern Great Northern being of such high quality that they are all unaffordable.