Construction of Line 1 started in September 1981 with the Construction and Development Corporation of the Philippines (now the Philippine National Construction Corporation) as the contractor with assistance from Losinger & Cie, a Swiss firm (today Losinger Marazzi), and the Philippine subsidiary of the U.S.-based Dravo Corporation.
Konstruksi Jalur 1 dimulai September 1981 dengan Construction and Development Corporation of the Philippines (sekarang Philippine National Construction Corporation) sebagai kontraktor dengan bantuan firma Swiss Losinger dan firma Amerika Dravo.