Classified 158, the trains began to appear in 1989. Called Sprinter Express, the name was based on British Rails wish to advertise the new acceleration ability the units had over older aging heritage DMU fleets. Their introduction saw a massive fall in journey times in the areas operated, with timetables quickly being updated to take advantage of these new trains.

The Class 158 soon became common place across the UK, operating short distance domestic services as well as long distance cross country trains. With carpeting throughout, full air conditioning, and provision for a trolley service during travel, passenger comfort and relaxation was vastly improved and warmly welcomed by customers.

Today a large number of different interiors have been adopted as private operators each seek to tailor their trains to customer needs. Various qualities of first class accommodation also exist. All seating in standard class compartments is in 2+2 formation, with first class sporting 2+1.