Paul Scott wrote:
wrote in message
...
What is it that they are actually doing? It seems almost to be every
weekend.

Rebuilding the 'sub surface railway' track and formation to mainline
standards throughout, so that the S stock will ride properly when
delivered.

I've seen precious little evidence of that yet. There has been significant
slaughtering of the trees on the embankments, though, north of
Rickmansworth - some pretty big ones at that.