The Tokyo Waterfront Area Rapid Transit 70-000 series (東京臨海高速鉄道70-000形電車) is an EMU which operates on the Tokyo Waterfront Area Rapid Transit. The train was built by Kawasaki Heavy Industries and first began revenue service in 1996. Its design is based on the 209 series. The trains were originally formed as 4-car (lengthened to 6 cars from 2002) sets for use on the Rinkai Line only, but 10-car formations were also delivered from 2002 for use on through services to/from the JR Saikyō Line. From October 2004, the fleet was reformed entirely as 10-car trains, with some surplus intermediate cars sold to JR East to create 209-3100 series EMUs used on the Kawagoe Line.