Simplify the following text for a Grade 9 native English-speaking person.
Original: The Light Rail Transit Association ( LRTA ) is a non-profit organization whose purpose is to advocate and encourage research into the retention and development of light rail and tramway\/streetcar systems .
Simplified: The Light Rail Transit Association ( LRTA ) is an association . Its purpose is to help and encourage research to keep and develop of light rail and tramway\/streetcar systems .