There’s an interesting photo-article in Wired UK showing the refurbishment of one of the twenty year old original Eurostar sets at their depot in Lille.
What the article fails to mention is that only a handful of the original sets will be receiving this treatment; the rest are going for scrap, replaced by new Siemens e320s. I can understand the logic for fleet replacement at this stage when the old trains contain a lot of dated technology and replacements result in increased operating efficiency. But I can’t think of a precedent, in Britain at least, for major mid-life refurbishment of just a minority of a fleet.
There is presumably a perfectly good reason for this, but I haven’t seen it expressed anywhere.