Northampton is situated near junctions 15, 15a and 16 of the M1 motorway. The A45 and A43 go through the town and the A14 is close by to the north. By rail, Northampton railway station is served by the Northampton Loop of the West Coast Main Line, and has regular services to London and Birmingham provided by Silverlink Trains (to London) and Central Trains (to Birmingham). Virgin Trains also provide some services to London and the north, with a small number of Pendolinos running each day. Sywell Aerodrome is the nearest airfield; for international links, East Midlands Airport and Luton Airport are quickly accessible by the M1, and Birmingham International Airport is accessible direct by train. Transport within the town exists in the form of buses run by two main companies; The Stagecoach Group and The First Group. National Express covers major routes between urban centres in Britain.