Simplify the following text for a Grade 9 native English-speaking person.
Original: Then known as Mass Rapid Transit Corporation ( MRTC ) when it was incorporated on 6 August 1987 , it was renamed as Singapore MRT Limited before taking on its current name , SMRT Trains , in the year 2004 .
Simplified: It was first known as Mass Rapid Transit Corporation ( MRTC ) when the company was founded in 6 August 1987 . It was renamed Singapore MRT Limited before becoming its current name , SMRT Trains in 2004 .