Simplify the following text for a Grade 6 native English-speaking person.
Original: The Class 379 Electrostar is a type of electric multiple unit ordered in April 2009 for Stansted Express services operated by National Express East Anglia .
Simplified: The Class 379 Electrostar is a type of electric multiple unit . It has been ordered by National Express East Anglia to run their Stansted Express services . .