This is a £7m office headquarters building of modern and innovative design, situated inside York's medieval city wall.

The project received strong support from the city council, English Heritage, the Ancient Monuments Commission, and local amenity societies. The building is naturally ventilated, employing heavy structure to limit temperature fluctuations. Fixed external louvres moderate solar gain, and air grilles above enable fresh air to be admitted to the centre of each floor plate from any point around the perimeter of the building. This air is ducted into local ‘void pack’ mechanical ventilation units, which fit between the primary structure in the suspended ceiling voids. Heating or cooling batteries and extra void packs can be flexibly added or removed to accommodate changing interior layouts.

An air-conditioned control room monitors the status of the rail network 24 hours a day, and co-ordinates maintenance work for approximately one third of the UK's rail network. Levels and ground structure were carefully designed to leave the critical archaeological layers, which underlie the site, undisturbed. The end result is a modern office building within a historic setting.