The Caldecott Tunnel (Bore 2: 28 0015, as well as Bore 1: 28 0015R) collectively refers to two tunnels for east/west traffic and the service buildings for the tunnels. The tunnels are 3,203 and 3,135 feet long and are made of reinforced-concrete lining. Important design features of the tunnels include the ventilation ducts throughout, as well as the two portal buildings built on top of the tunnels. The reinforced concrete Art Deco style portal buildings were designed to ventilate the tunnels and feature large pilasters, large multi-light fixed windows, decorative chevrons, medallions, and a decorative American eagle. The use of cast aluminum in light transition structures and sconces along the approaches are also notable.