The annual report from the Office of Road and Rail found that HS1, whose domestic services are part-operated by Southeastern Railways, met or exceeded targets for delays and financial performance in 2015-16.
The St Pancras – Ashford International line, operated by Southeastern, saw much faster growth than expected with an extra 1,750 trains being added to the network.
During the period, it helped HS1 generate income of £70.5m - £4.6m higher than predicted - while operating costs were £0.5m lower than forecast.
Keolis UK operate Southeastern as part of the Govia franchise, which has run the high speed rail service between St Pancras and Ashford International since 2009, transporting 640,000 passengers a day.
Read the full ORR report.