Not quite sure how succesful this project is going to be, to be honest.

This is one of three "recreation" projects that have been proposed in the past few years for scrapped BR diesel classes and the only one that has made any significant progress is the "Baby Deltic" Class 23 - a single engined version of the Class 55 Deltics used on the London-York-Edinburgh line , which were used on Suburban trains out of London, Kings Cross. They weren't particularly reliable, hence their early demise (late 1960's for all bar 1, which was used on test trains until the mid '70s). An original engine from one has been fitted in a Class 37 bodyshell (and test run) with the intention of making changes to the 37 shell - like shortening the noses at each end - to recreate a Class 23. Current progress can be seen on their website.....

http://www.thebabydelticproject.co.uk/

Another group set out to build one of the original LMS mainline diesels from 1947, but after quite a lot seeming to happen in a short space of time, it has all gone very quiet....

http://www.lms10000.org/

As regards the "Class 22", I believe some of the powerplants were sold off for use to power backup generators in hospitals/factories, so they may at least be able to obtain one of those - which may be what the "important news" could be.

Te UK steam "new build" scene continues to expand, so nothing to stop the same happening for diesels - assuming the money/expertise is available, of course!

Building an 'extinct' diesel type is far more reasonable a project than a steam locomotive, but it's also not going to garner public support like a steam engine would.
As I understand it, the "Tornado" project got plenty of money from 'average', non-railfan people in the UK.
Think of Doyle's amazing ALCO PA project in Portland. Folks like us are salivating at the idea of someday seeing it at the head of a train, alone. But how many average folks are looking as forward to that, as opposed to seeing 4449 in steam again once it's 15-year rebuild is complete later this year? Not many, I'd suspect. I've watched people walk right past that PA at the Portland enginehouse, headed directly for steam, completely oblivious of the rarity of that diesel sitting there.

I bet this is a different scenario in 20 years...

In the UK, I doubt if most people would know what a Class 22 was, let alone want to contribute money towards building a new one!
They had a fairly short working life, 12-13 years maximum, with the last ones going in 1972 - ie 43 years ago - and they were based in the west of the Country, so you had to visit the former GWR lines to see them in action. True, the BR diesel-hydraulics did get quite an enthusiast following in their latter years, particularly the Class 52 "Westerns" that lasted to 1977, but this is a project that will cost an awful lot of money and one wonders who is likely to contribute. The "Tornado" project was something that caught the imagination of the General Public, coupled with the large numbers of steam enthusiasts of the 1950's & 60's who remembered them in service and are now the "right age" (ie 60+) to have disposible income to contribute to the pot. The A1 Trust appear to have got everything right in that respect and their latest "P2" 2-8-2 project is just as succesful.

Diesel preservation here has rapidly grown over the last 30 or so years, basically from nothing, but at least it was a lot easier for followers of a particular class to buy them straight from service from BR or industrial users rather than start from scratch, which is rather a different ball game.

A North American analogy would be something like a Baldwin "Centipede" or "Shark" new build - just how many people would be attracted to contributing to that project, and would you get money from anyone other than Railfans?

It is understood that the "important news" about the 22 does relate to obtaining a power unit, so we will have to see what happens next.

I've lost count of the number of "new build" steam projects that appear to surface in the UK on a regular basis nowadays, a fair proportion of which will never see the light of day. About half a dozen of them are now at the "metal cutting" stage - mainly the frames - and some of those are now well advanced (like the "Patriot" project), but the more projects, the more competition from the same "pot" of enthusiast money, unless you can extract money from the non-enthusiast market.

I'm not so sure about that!

Depending on whether you're building on an existing locomotive "platform" and are only modifying noses or something, or whether you are building a whole new locomotive around a prime mover, it could well be more challenging to build a replica diesel. I'm thinking of the prospect of bending a lot of metal into complex shapes (think of an F-unit nose, and some others), and more importantly, all the subsystems a diesel has for cooling its water and oil, the air rack setup (to use EMD terminology), and of course all the wiring, relay cabinets, etc., plus in at least one case getting appropriate trucks and the hydraulic-mechanical transmissions--

I'm thinking of the considerable effort going into a Southern Pacific KM unit in California, where that group had to wait years before a set of trucks came available that still had all the gearboxes and drive shafting equipment intact--and they still have to get a replacement engine (one of the two prime movers apparently has water damage and is likely beyond repair)--not to mention refabricating the whole front end after the unit had been modified as a camera car for a locomotive simulator.

Steam may be challenging, parts might be big and heavy, but it's nowhere near as complex as a diesel and most of those parts aren't quite as delicate and thus don't require as much precision as some of the technology in a diesel.

On the other hand, if we can get to that stage--well, what would you like to see? Baldwin Centipede? FM Erie-builts, maybe a whole A-B-A set? Ditto for Baldwin passenger Sharks (unique to the PRR, and styling influenced by the T1 steam locomotive)? Replacement B-units for existing Alco PAs and Baldwin Sharks?

Better head for that bomb shelter. . . .

I truly doubt even among train buffs, you'd get a great deal of coin for such a project.
And the fact that named diesels are pretty old now, seems to shoot down the "wait 20 years" theory.
Just ask around on the PA project. Only hardcore train buffs know or even care. Like I wrote earlier, I've watched the public walk right past Doyle's PA project like it was not there, to get to the steam locomotives. And these are folks were only would have known diesels in their lifetimes on the mainline RRs.

But imagine if Doyle had restored the PA1 to original Santa Fe war bonnet colors. Visitors' jaws would drop, hearts would go into fibrillation, people would have religious conversions, and very possibly peace would break out all over the world. The NKP blue paint is depressingly uninspiring. Doyle, how could you?