This sounds to be nothing more than a flight of fancy given that the operator of the East Coast franchise in 2016 is not yet known, as the new franchise is still a while away from being awarded, and hence it is not possible to know what the chosen operators' rolling stock policy will be. The IEP train order is known as it is sanctioned by the DfT rather than being entirely down to TOC discretion.
Additionally it would be ludicruous if the IC225s ended up being replaced by Pendolinos ahead of the replacement of the HSTs, which are 10 - 15 years older, by IEP.
The
West Coast franchise was due to take delivery of a new fleet of trains that were widely speculated to consist of 6-car "Baby Pendolinos" in 2016 during the First Group franchise, but even this is now no longer a given, now that the franchising process is completely up in the air again.
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The idea of ordering two new sets of different train is very unlikely. If the idea is to replace the 91/mk4 sets as well, I'm sure this will be done with more IEP vehicles. Certainly from what I've read this is a possibility, by 2020.
Indeed, there is a future option for 30 x 9-car IEP electric trains covering 26 diagrams to replace the 225s at some point after the initial GWML and ECML IEP fleets have been delivered.