Silverlink was a train operating company in the United Kingdom owned by National Express Group that operated the North London Railways franchise from March 1997 until November 2007. At the end of 2007 Silverlink Metro services were taken over by London Overground and Silverlink County services were taken over by London Midland. The North London Railways franchise was awarded to National Express on 7 February 1997. National Express commenced operating the franchise on 3 March 1997. After initially trading as North London Railways, in September 1997 the franchise was rebranded as Silverlink.