Kings Cross rail station in London will be closed from Saturday, February 17 to Tuesday, February 20.
This from the TFL email:
King's Cross National Rail station closure
From Saturday 17 until Tuesday 20 February, there will be no long-distance trains from King’s Cross National Rail station due to Network Rail signalling upgrade work.
For travel to destinations on the East Coast Main Line such as Peterborough, Cambridge, Yorkshire, the north east and Scotland, use alternative national rail services from St Pancras, to connect with rail replacement buses. A very limited Great Northern service will run from King’s Cross to Potters Bar (except on Sunday).
For full details of services affected, alternative transport and to plan your journey visit the National Rail website.