Task: Text Simplification
Input (English): Docklands Light Railway rolling stock is the passenger trains and service vehicles ( collectively known as ' rolling stock ' ) used on the Docklands Light Railway ( DLR ) , which serves the London Docklands area in the east of London .
Output (English): Docklands Light Railway rolling stock means the passenger trains and service vehicles used on the Docklands Light Railway ( DLR ) in London , England .