Question to the Department for Transport:

To ask the Secretary of State for Transport, if he will request that train operating companies publish the criteria they use for calculating rail fares.

The rail fares we regulate have been capped at inflation (Retail Price Index) for three years running, and will continue to be capped for the life of this parliament. The Government sets the maximum amount by which regulated fares can rise. Details of how fares regulation applies to train operators can be found in Schedule 5 of the Franchise Agreement which can be found on the Department’s website. Other fares are unregulated, and train operators are permitted to set these on a commercial basis.

https://www.gov.uk/government/collections/public-register-of-rail-passenger-franchise-agreements