Function and design

Class A4 'Pacific' loco 'Union of South Africa' at Edinburgh Waverly this evening having worked a rail tour into the station. Designed by Sir Nigel Gresley and constructed in 1937, numbered firstly as LNER 4488, then LNER 9 and after nationalisation of the railways BR 60009 it was only allocated to Edinburgh Haymarket shed then later Aberdeen. Preserved after withdrawal this A4 has been constantly active on heritage lines around Britain alongwith working charter trains on the mainline. Phew, just scraped this on before midnight!