But how long would it take to design, tender, award and build replacement trains? Could these refurbished fleets could be at the end of their lives by the time new stock comes on stream even if ordered fairly soon?
Design will be quite short assuming it is a derivative of recent multi system high speed train from Europe. HS1 is basically a French Ligne a Grand Vitesse clone. Unlike UK the continental partners buy the off the shelf version and just change things like the cab signalling modules, seating and livery.
Tender time varies by organisation, some countries do this in weeks, others get bogged down in lots of tiny detail specs. Of course the more you faff with a design that works the more risk that you introduce something that is troublesome
The original fleets (and those that were in Thayls Red) are all getting towards end of their lives. Probably worth quick history lesson here to explain better. The first generation TGV (for Paris-Lyon) had 12 motors too, like the original Eurostar the outer bogie under passenger carriage adjacent to power car was also motored. By the time Atlantique TGVs were built synchronous motors had been developed and units went to just 8 more powerful motors. Eurostar were 2 half units so had 12 motors rather than 8 per 200m unit.
The Atlantique units (built about 1989 -1992) had 10 trailers as platforms were longer, but a follow on regional order was standard 200m length with 8 trailer cars. The Eurostar E300s were built around same time (1993-1996) as Reseau (regional) units. The Thayls (red) units were basically a 3 voltage version of regional trains (and French had some 3 voltage regional ones for going over the border into Italy too). The final batch for Thayls had 4 voltage power cars to operate into Germany, these were based on new power car bodyshell designed for double decks TGV which started in mid 1990s. As double deck units were introduced they took over the busier workings and relegated first generation to more fringe services.
So basically the E300s are now around 30th birthday and the trains they were derived from are being replaced by latest (5th) generation in next few years (many have already been replaced, but some are getting short life extension as below). SNCF has placed orders (and more recently extra orders taking total to 115) Avelia Horizon units with delivery from this year though the next 10 years. It would be quite easy to piggyback off these orders (or even swap some of the delivery slots around) if Eurostar wanted clones of these to replace E300s.
About 6 months ago, due to demand SNCF decided to do life extension to about 100 older sets for 2 to 10 years until the new trains (as above) are ready, length of extension depends upon condition. There are currently about 363 active TGV sets.
Renovation covers 28 Atlantique sets, 26 dual voltage Reseau (regional) sets, 26 tri voltage reseau sets, plus 6 sets used on services to Milan. Also 23 sets of the earliest double deck units are getting 10 year life extension and being refitted similar to recent Oceane spec (
Rames Nouvel Aménagement Intérieur)