There have been concerns that premium fares will be charged for those using the new high-speed line whose first phase, from London to Birmingham, is due to open in 2026.
Passengers travelling on domestic services using HS1, the 186mph Channel Tunnel fast link, pay much higher fares than those using "conventional" Kent commuter services.
The Rail Delivery Group (RDG) said "setting fares at the right level" was one of its five key priorities for HS2.
Legislation for the first phase is currently going through Parliament, with a second, Y-shaped, phase, taking the line to north west and north east England due to be completed around 2032/33.
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