M25 motorway and Thurrock off junction 31 (to the east of London). Cobham services opened on 13 September 2012. Originally, the M25 was unlit except for sections around Heathrow, major interchanges and Junctions 23–30. Originally, low pressure sodium (SOX) lighting was the most prominent technology used, but widening projects from the 1990s onwards have all used high-pressure sodium (SON) lighting and this has diminished the original installations. By 2014 only one significant stretch was still SOX-lit (Junction 25–26) and the units were removed the same year. The motorway passes through five counties. Junctions 1A–5 are in Kent, 6–14 are in Surrey, 15–16
London Underground infrastructure in 1999, and key interchange stations such as King's Cross St. Pancras, Victoria station and Green Park becoming step-free. Over 28 stations will become step-free over the next 10 years, taking the total step-free stations to over 100. In October 2015, TfL installed the first incline lift on the UK transport network, at Greenford station. The London Underground comprises eleven lines. London Underground trains come in two sizes, larger sub-surface trains and smaller deep-tube trains. Since the early 1960s, all passenger trains have been electric multiple units with sliding doors and a train last ran with a guard in 2000.