Extend the training AND extrapolation range up to 3 TeV

Given the project of extending the training up to 3 TeV, this should be done together with the extension of the extrapolation range up to 3 TeV.

Tagging cpollard, fdibello (training) and mfoti (extrapolation).

This ticket is to keep track of the progress and discuss issues if needed.

Cheers

Matthias