ORCATS is a large centralised legacy

Legacy system

A legacy system is an old method, technology, computer system, or application program that continues to be used, typically because it still functions for the users' needs, even though newer technology or more efficient methods of performing a task are now available...

 computer system used in the UK. It is used for real time reservation and revenue sharing on interavailable tickets between Train Operating Companies (TOCs). The system is used to divide ticket revenue when a ticket or journey involves trains operated by multiple TOCs. The system was owned by British Rail

British Rail

British Railways , which from 1965 traded as British Rail, was the operator of most of the rail transport in Great Britain between 1948 and 1997. It was formed from the nationalisation of the "Big Four" British railway companies and lasted until the gradual privatisation of British Rail, in stages...

, and is now managed by the Association of Train Operating Companies

Association of Train Operating Companies

The Association of Train Operating Companies is a body which represents 24 train operating companies that provide passenger railway services on the privatised British railway system. It owns the National Rail brand. The Association is an unincorporated association owned by its members...

.