Cathays railway works the Cardiff Valleys Division, under the Loans and Guarantees Act (1929): the track layout was improved; a new corrugated roof installed; and a new ramp added to the GWR standard-pattern single-road coaling stage. By 1950 under British Railways, the combined depots of Cathays and Radyr (Code:88A), had a complement of 82 locomotives, all tank-types: 2x2-8-2T; 62x0-6-2T; 15x0-6-0T; 3x0-4-2T. In 1959 the shed was divided to cope with the introduction of diesel multiple units. In 1961 the shed closed to steam, and all steam locomotives were moved to Radyr. The shed closed completely in November 1964, with the opening of the
Fairwater, Double Bay company, only for it to collapse (in a major stockmarket downturn) three years later. Lady Mary Fairfax (née Marie Wein, 1922-2017) established the Australian Opera Auditions in 1964, in cooperation with the Metropolitan Opera in New York. This was the first of a string of charitable organisations connected with the arts which she joined or initiated. She had lived at Fairwater since 1968, where she conducted a never-ending salon where guests were able to admire the art works of Rodin, Epstein, Dobell and Degas. Among those she entertained were actor Rudolf Nureyev, politician Pierre Trudeau, actor Phyllis Diller, entertainer Liberace,