Euston St Pancras railway station

From the Wikipedia page

Euston St Pancras railway station is a proposed station on the future Crossrail 2 line in the United Kingdom linking Hertfordshire and north-east London to south-west London and Surrey. Construction is expected to begin in the 2020s.

It would be a "mega station" serving the existing Euston, King's Cross and St. Pancras main line stations. If funded and completed, it will be one of two such stations on the Crossrail 2 route (the other being Dalston).