Simplify the following text for a Grade 9 native English-speaking person.
Original: The body for coach 17 was built in 1911 , by local firm Shapland and Petter , and mounted on a steel underframe constructed by the railway in its own workshops at Pilton .
Simplified: The body for coach 17 was built in 1911 by a local firm , Shapland and Petter , and fitted to a steel underframe made by the railway at Pilton .