M25 motorway Europe's second longest orbital road after the Berliner Ring, which is . Originally built almost wholly as a dual three-lane motorway, much of the motorway has been widened: to dual four lanes for almost half, to a dual five-lanes section between junctions 12 and 14 and a dual six-lane section between junctions 14 and 15. Further widening is in progress of minor sections with plans for managed motorways in many others. To the east of London the two ends of the M25 are joined to complete a loop by the non-motorway A282 Dartford Crossing of the River Thames between Thurrock
West London Orbital sections: The Dudding Hill Line, the North London Line and the Hounslow Loop. The Dudding Hill line itself has had no scheduled passenger service for over a century. It has no stations, no electrification and a 30 miles per hour (48 km/h) speed limit with semaphore signalling, and is lightly used by freight and very occasional passenger charter trains. It is roughly 4 miles (6.4 km) long. Near the site of Old Oak Common the West London Orbital would connect to the existing North London Line, and then further south at Acton, use the link down to the Hounslow Loop