According to a press release sent out this morning, the new series is being developed under the working title "Thunderbirds Are Go." The basic synopsis seems to hew pretty closely to the original, focusing on the globe-trotting Tracy clan of Incredible Rescues as they "[pilot] their incredible vehicles into impossible rescues across the globe."
The original "Thunderbirds" ran for two seasons beginning in 1965, followed by a 1966 feature film including the original voice cast.
The new series is being developed for ITV Studios in the UK with the creative end being handled by Puekko Pictures.
From Weta and Puekko co-owner Richard Taylor:
Thunderbirds was a hugely influential television series in my childhood. Having watched it originally in black and white, it was only years later that I discovered the full and rich world that Gerry and Sylvia Anderson, Derek Meddings, Mike Trimm and their team created. It is thrilling therefore to think we have the opportunity to work with ITV on this new series inspired by this most wonderful of British shows. I personally, together with the teams here at Pukeko Pictures and Weta Workshop, look forward to designing and creating an inspirational world that will engage the imagination of a whole new generation as it did for us nearly half a century ago.
Given the source material, we would almost be disappointed if it didn't have some kind of unique visual hook like the Andersons' "Supermarionation"--in this case, the series reboot will be a blend of CG-animation with live-action backgrounds. I have a clear idea in my head of what that looks like (instead of trying to blend the CG characters in, Weta would make them stand out more to increase the surreality), but would love to see some concept art to know what the effects company has in mind.