 In 2009 Network Rail installed a 12-car turnback siding just south of Tunbridge Wells station between the Grove Hill and Strawberry Hill tunnels to facilitate a more frequent service and to allow restricted types of London trains starting or terminating at Tunbridge Wells to be operated in 12-car formations.Previously such services were 11-car at most.Average daily passenger flows on trains between Tunbridge Wells and London have increased from about 10,000 in 1999 to over 12,500 in 2008, a compound growth rate of about 2.5% per year.