Simplify the following text for a Grade 9 native English-speaking person.
Original: The British Rail Class 47 ( Originally Brush Type 4 ) is a class of British railway diesel-electric locomotive that was developed in the 1960s by Brush Traction .
Simplified: The British Rail Class 47 , is a class of British railway diesel-electric locomotive that was developed in the 1960s by Brush Traction .