The longer international platforms, used by Eurostar, extend into Barlow's train shed, whilst the other platforms terminate at the southern end of the 2005 extension.
The international platforms do not occupy the full width of the Barlow train shed, and sections of the floor area have been opened up to provide natural light to the new ground-level concourse below.
 Eurostar's arrival and departure lounges lie below these platforms, adjacent to The Arcade, a concourse fashioned from the original station undercroft which runs along the western length of the Barlow train shed.
 The southern end of The Arcade links to the western ticket hall of King's Cross St Pancras tube station.

Access to the East Midlands Railway platforms are via the northern end of The Arcade, while the Thameslink and domestic High Speed platforms are reached via a street-level concourse where the old and new parts of the station meet.
The main pedestrian entrance is at the eastern end of this concourse, where a subway enables pedestrians to reach King's Cross station and the northern ticket hall of the tube station.
The longer international platforms, used by Eurostar, extend into Barlow's train shed, whilst the other platforms terminate at the southern end of the 2005 extension. The international platforms do not occupy the full width of the Barlow train shed, and sections of the floor area have been opened up to provide natural light to the new ground-level concourse below.  Eurostar's arrival and departure lounges lie below these platforms, adjacent to The Arcade, a concourse fashioned from the original station undercroft which runs along the western length of the Barlow train shed.  The southern end of The Arcade links to the western ticket hall of King's Cross St Pancras tube station.
Access to the East Midlands Railway platforms are via the northern end of The Arcade, while the Thameslink and domestic High Speed platforms are reached via a street-level concourse where the old and new parts of the station meet. The main pedestrian entrance is at the eastern end of this concourse, where a subway enables pedestrians to reach King's Cross station and the northern ticket hall of the tube station.
St Pancras railway station