Simplify the following text for a Grade 12 native English-speaking person.
Original: The Class 220 Voyager is a class of diesel-electric high-speed multiple-unit trains built by Bombardier Transportation for the British train operating company Virgin Trains , but are now operated by CrossCountry .
Simplified: The Class 220 Voyager are a class of diesel-electric high-speed multiple-unit trains built by Bombardier Transportation in 2000 and 2001 .