Original: The design was successful and led to the development of the similar Class 320 and Class 322 units for use by Strathclyde PTE and Stansted Express (now used by First ScotRail) respectively.
Simplified: The design was very successful and led to the development of the similar Class 320 and Class 322 units for use by Strathclyde PTE and Stansted Express (now used by First ScotRail) respectively.