Simplify the following text for a Grade 7 native English-speaking person.
Original: The line started service on 10 May 1982 with a total cost of construction ( not adjusted for inflation ) at HK$ 4.1 billion .
Simplified: The line started service on 10 May 1982 with a total cost of construction ( not adjusted for inflation ) of HK$ 4.1 billion ( US$ 526 million ) .