Simplify the following text for a Grade 12 native English-speaking person.
Original: There was some question over the legality of using the old Routemaster under the Disability Discrimination Act 1995 as the Routemasters were inaccessible for wheelchair users .
Simplified: There was some question over the legality of using the old Routemaster under the Disability Discrimination Act 1995 as the Routemasters effectively banned wheel chair users .