It is the Science Museum that has the power of designating important
The functions and scope of the RHC are set out in the Railway Heritage Act 1996 ("the 1996 Act"). The RHC is responsible for identifying and designating records and artefacts of the railway industry that are of sufficient interest to warrant preservation and it considers proposals for disposal by the owners of such items.
When the RHC was abolished it was
There was strong support for the Board of Trustees of the Science Museum being ideally placed to take on the role in the future, especially if it appoints external panel members to ensure that there is no conflict of interest between it carrying out the designation function and its role as the governing body of the National Railway Museum.
So from 2013, with the abolition of the Railway Heritage Committee, the Science Museum decides which railway artefacts are of sufficient importance to be designated for preservation.
Members of the Railway Heritage Designation Advisory Board (RHDAB) are appointed by the Board of Trustees of the Science Museum Group for a term of three years.
Members are drawn from the railway industry, the archives and records offices, the museum world, and the heritage railway sector.
Established on 1 April 2013, the RHDAB meets three times a year to recommend artefacts and records for designation by the Board of Trustees of the Science Museum Group.
Source
https://publications.parliament.uk/pa/ld201213/ldselect/ldsecleg/66/6603.htm and
https://www.sciencemuseumgroup.org.uk/about-us/railway-heritage-designation-advisory-board/
