It performs industry-wide communications, defines ticket validity, participates in the formulation of railway policy, and is responsible for the National Rail Enquiries service.

The current RDG has its roots in two preceding organisations, the Association of Train Operating Companies (ATOC), and the Rail Delivery Group.

The original Rail Delivery Group was established in 2011 to formulate policy and undertake communications on behalf of the entire railway industry, its membership having comprised all passenger and freight operators in the UK.

[7] The RDG describes its primary purpose as enabling train operating companies and Network Rail to deliver better services for end customers.

[15] The RDG's public relations activities include the sponsorship of various schemes, such as PlusBus, PlusBike, and Bike and Go,[16][17] as well as staff travel arrangements for both current and retired railway employees.

[22] The RDG is partially responsible for railway policy formulation; it works with the Rail Supply Group and other parties to coordinate shared objectives.

[28] In response to the 2022 Russian invasion of Ukraine, the RDG quickly led a scheme to provide free rail travel to Ukrainian refugees fleeing the conflict.

[30] Throughout the 2010s, in coordination with the Office of Road and Rail, the organisation worked to open the supply and operation of this equipment to greater market competition.

[32] The RDG worked with the Department for Transport and other entities to support the rollout of contactless payment methods in the South East of England by the end of 2023.