Two practices to work with UK engineering firm Mott MacDonald on first three modules of controversial Saudi megaprojectNeoms vision for the first phase of The LineGensler and Vienna-based practice Delugan Meissl Associate Architects have been handed key roles on the first phase of The Line in Saudi Arabia.The two firms will collaborate with UK engineering consultancy Mott MacDonald on the first three modules of the 170km-long megaproject, itself part of a much larger developing region called Neom.Scheduled to complete in 2045, The Line is envisaged to have a total of 140 modules, each measuring 800m long, 200m wide and flanked by two parallel 500m high walls with the completed scheme expected to house nine million people.Delugan Meissl Associate Architects (DMAA) has been appointed as urban designer by Neom and will lead the concept and detailed masterplan for the first phase.The practice will also continue to support Neom on later phases of the project to maintain its design vision on the first phase as further architects are appointed.> Also read:Saudi Arabia to scale back plans for The Line, say reportsGensler has picked up a role as city planning consultant on the first three modules and will lead on city design coordination and city planning while leading on governance across the project on areas including planning policies, frameworks, land use and design compliance.The worlds biggest practice has also been appointed as city asset design architect for critical city infrastructure, including transport hubs and public realm.Source: NEOMThe linear city will be flanked by two 500m high walls covered in mirrored claddingMott MacDonald has joined as city infrastructure engineer, tasked with driving management and control of the schemes vertical and horizontal structures and utility systems.The Lines chief development officer Denis Hickey said the project had established a unique partnership that brings world-leading city design and engineering expertise to deliverphase one.He added: Collaboration is at the core of this, with a city-wide best practice group that will showcase how innovation can change the way we consider, design and build cities forever. This reflects NEOMs vision and global ambition.Other developing projects in Neom, which will stretch across 26,500sq m of desert in Saudi Arabias north western Tabuk Province, include a floating octagonal industrial complex and the Arabian peninsulas first outdoor ski resort.Neom, Gensler, DMAA and Mott MacDonald have been contacted for comment.