The two companies are responsible for supplying 63 metro cars, which are being manufactured by JR East's Japan Transport Engineering Company (J-Trec), installing railway systems, and maintaining the line for 10 years. Delivery of fleet will be completed in January 2016 in time for opening of the line in March, which is two months ahead of the original schedule.

The 23.5km 16-station Purple Line will link Bang Yai on the existing metro Blue Line northwest of Bangkok with Bang Sue. The Baht 60bn ($US 1.7bn) project is being developed by the Mass Rapid Transit Authority of Thailand (MRTA) under a public-private partnership (PPP) scheme funded by a Japanese ODA loan. MRTA awarded a contract in 2013 to Bangkok Metro Public Company (BMCL) for both the provision of the railway systems and operation of the line.

Ch Karnchang (CK), which is a shareholder in BMCL along with MRTA, has been responsible for the civil works. Marubeni and Toshiba is providing the railway system as a full package, including rolling stock, power supply systems, signalling and control systems and communication systems.