History sidebar:
Flying Scotsman was built by the Great Northern Railway in 1922, the third of the A1 class, numbered 1472. In 1923 the railways were "grouped" and Flying Scotsman passed to the LNER which added 3000 to the GN numbers, making it 4472.
After WW2, the LNER started to renumber its locomotives and FS received 502, but before the scheme was completed (or even barely begun!) they came up with another system, and FS became 103. Someplace along the line, the class was improved, with higher boiler pressure and a steam dome shaped like a banjo case and became class A3. (the unimproved ones became class A10, because another engineer wanted to use class A1.) In 1948 the railways were nationalized and BR added 60000 to the LNER numbers, so it became 60103. Under BR it was painted black and then Brunswick green (original colour was apple green) and carried smoke deflectors at one time.
When it was sold to Alan Pegler, it went back to being LNER 4472, and acquired a second tender.
Second item: one of the oldest trains running out of London was the "10 am Scotch Express". This train was the prestige train running on the east coast lines to Edinburgh, and was nicknamed "The Flying Scotsman". The name was used as a locomotive name in 1922, but the loco and train did not always go together. Many of the locos were given corridor tenders to allow them to run non-stop from London to Edinburgh -- the engine crew changed over at the halfway point.