If this were a sporting event it would be the World Cup or perhaps the Olympic Games. A better metaphor, however, insists curator Robert Gwynne is a musical one. "It is a rock 'n' roll concert for rail enthusiasts," he explains. "It's capable of reminding everyone just how romantic and warm and friendly railways can be as well as how essential they are to our day-to-day lives," he adds.
For such railway enthusiasts, or puffer-nutters as they refer to themselves, the assemblage of 50 record-breaking locomotives next to the National Railway Museum in York represents the biggest gathering of locomotive superstars ever seen in one place.
By the time the first of the estimated 100,000 fans begin flooding through the turnstiles at Railfest 2012 today there will be on display the world's fastest steam locomotive; the newest, the oldest and of course the most famous – the Flying Scotsman – among dozens of other record holders.
But yesterday with just a few hours to go before the whistle there was a mood of quiet determination as the teams of dedicated volunteers set about polishing, oiling and firing up their mighty charges.
Standing on the footplate of the City of Truro, a prewar Great Western Railway loco which once clocked up 102.3mph between Plymouth and Paddington, Britain's oldest working boilersmith was looking back on a long career. "There was none of the glamour of the guard or the fireman for us. Just lost fingernails and plenty of bruised heads in the maintenance department," recalls Gordon Reed, 78. "This is Britain's greatest gift to the world and even in these days of privatisation there is a great community on the railways," he says.
Newer recruit Laura Hester, 34, was applying the Brasso to the steaming iron hulk's gleaming nameplate. The science explainer only got to drive her first steam train on a corporate team-building exercise two years ago but was immediately hooked.
Since then she has passed out as a fireman and is training to be a driver. She admits it is a bit of a man's world though that is changing. "There are a surprising amount of women involved but you do get a bit of a double take sometimes when people see you although you get plenty of mums saying to their daughters 'look there is a lady on the footplate'," she says.
There were certainly no women drivers in Caleb Priestley's days. Now aged 93, he started off as a cleaner on the railway near Barnsley in 1936 working his way up through the ranks. During the war he was called up to drive trains for the military and was part of an elite group sent to operate the vitally strategic Iranian railways between the Persian Gulf to the Caspian Sea.
Following the Allied invasion of Italy he was dispatched to take over the network, moving troops, supplies and prisoners. In the 1970s he became something of a celebrity when he set a new record by driving one of British Rail's new high speed trains at 143mph between Darlington and York – a feat that was unsurpassed for nearly a decade.
"I wish I felt a bit younger and then I could join in with things. It makes me feel I want to be part of it. I have been a railwayman all my life and I am very proud of that. If I could live over again I would do exactly the same thing. I loved being a fireman and I loved being a driver," he says.
For Alan Middleton, 74, a former engineer from Preston, Lancashire, who has helped restore the 1863 Furness 20, the oldest surviving working steam locomotive which spent 90 years ferrying coal from pit to Barrow steelworks before being left to rust, the attraction is simple. "I just like old engines. Victorian machinery is a joy to behold. The engine parts are all original. Stuff today is designed to last 10 years and then drop to pieces," he says.
But, explains Steve Davies, director of the National Railway Museum, Britain's railways never stop evolving and the future preservation of our transport heritage continues to pose challenges. The size of modern train units, which come in three or four carriages, means that future exhibition spaces will have a spatial problem to deal.
Only those assets which are of true technological significance – such as the British Rail Class 60 diesel or the InterCity 125 – will in future make the cut. Meanwhile, over the next 25 years there will be a phasing out of old Victorian semaphore signals, so again decisions must be made on which are retained and how they will be made available to the public
Yet despite the Government's quango cull which did for the Rail Heritage Committee, there remains a strong commitment to preserve the best of the current system within Network Rail and the Science Museum group, which took over its functions, he says.
Meanwhile the volunteer armies that regularly maintain and reclaim Britain's rail heritage continue to go from strength to strength, spawning thriving new industries.
But it is important not to overdo the romance and the nostalgia about our railway past, insists Mr Davies.
"The past is some place that the British always turn to for comfort," he says. "But the railway today is far superior in virtually every aspect of the past. It is cleaner, faster, more frequent and safer than it ever was."