M4 corridor bridge, serving Chepstow, being renumbered the M48, although the area is still generally considered as falling within the M4 corridor. Since the start of the 21st Century there has been evidence of more investment west of Cardiff, such as: M4 corridor The M4 corridor is an area in the United Kingdom adjacent to the M4 motorway, which runs from London to South Wales. It is a major high-technology hub. Important cities and towns linked by the M4 include (from east to west) London, Slough, Bracknell, Maidenhead, Reading, Newbury, Swindon, Bath, Bristol, Newport, Cardiff, and Swansea. The area is also served
M4 Tractor M4 Tractor The M4 High-Speed Tractor was an artillery tractor used by the US Army from 1943. The M4 was based on the chassis and drive train of the obsolescent M3 Light Tank which introduced the trailing idler. One variant was designed to tow the 3-inch or 90 mm anti-aircraft gun, and another was for the 155 mm gun or 8-inch howitzer. The rear compartment carried the gun crew and other equipment and some later variants included a crane to assist with heavier projectiles. Two types of ammunition boxes were used on all models: a 90 mm box with side