Simplify the following text for a Grade 9 native English-speaking person.
Original: The British Rail Class 304 electric multiple units were built for suburban use on the first phases of the West Coast Main Line electrification between Crewe and Manchester\/Liverpool\/Rugby .
Simplified: The British Rail Class 304 is a type of electric multiple unit . They were built for suburban use on the first phases of the West Coast Main Line electrification between Crewe and Manchester\/Liverpool\/Rugby .