was re-modelled and re-signalled, being incorporated into the West Midlands ICC take over control as Oxford (exclusive) in 2016. Most of the route from Birmingham Snow Hill to Wolverhampton is now used by the Midland Metro light-rail system, which diverges from Network Rail's Jewellery Line at The Hawthorns. The route between Marylebone and Leamington/Bordesley was used by open access operator Wrexham & Shropshire's services from London to Wrexham via Tame Bridge, Wolverhampton and Shrewsbury, which comprised three Mk3 coaches hauled by Class 67 diesel locomotives. Since these were neither Sprinters nor HSTs, they were restricted to lower line speeds, e.g. between Princes Risborough and Bicester, and between Leamington and Bordesley, although they were permitted to travel at between Bicester and Aynho. Wrexham & Shropshire had negotiated with Network Rail to allow its trains to travel at higher speeds on these sections, which required it to show that they had sufficient brake force to stop from such speeds within the signal spacings. Only the little-used line from Northolt Junction to Paddington has not been improved. In September 2006, Chiltern completed its "Evergreen 2" upgrade project, carried out by Carillion, which realigned the track through Beaconsfield to increase non-stop speeds from , installed additional signals between High Wycombe and Bicester North and between Princes Risborough and Aylesbury, and added two platforms (Nos 5 and 6) at Marylebone, on the site of the daytime carriage sidings, replaced by the new Wembley Light Maintenance Depot, just south and west of Wembley Stadium station. The new platforms and partial resignalling of the station throat make it possible to run 20 trains per hour in and out of the station. At weekends during 2008, when major engineering works were taking place on the WCML, the line was used by Virgin Trains' - "Blockade Buster" service via Willesden, Acton Main Line, Ealing Broadway, Greenford, High Wycombe, Banbury and Coventry, using pairs of five-car class 221 sets. Infrastructure Tunnels and viaducts There are several major civil engineering structures along the route of the Chiltern Main Line. The viaduct (Chalfonts No. 1 (Misbourne) Viaduct) crossing the M25 between Denham Golf Club and Gerrard's Cross is especially noted as a local landmark, as for many years it has borne a graffiti slogan, "" painted in large white letters on the south-facing parapet. The graffiti was partially removed in 2018. Oxford Connection A quarter of a mile (about 0.3 km) of