It is well known that the Hogwarts Express, the famous red steam train which is traditionally used to transport students to and from Hogwarts at the beginning and end of term, is the only magically operated steam train in the world. The work required to get muggles to lay hundreds of miles of unnecessary track, and to then conceal it from them was an expensive undertaking indeed, but what is not so well known is that it was not the relative expense which caused it to be the first and last of its kind.
After completion of the Hogwarts Line, and the inaugural journey of the Express, carrying many of the great and the good of Wizarding high society, enthusiasm for muggle steam trains was at an all time high. The result was the planned 'Anglesey Flyer'.
With the sizeable wizarding population on the island of Anglesey, and at the encouragement of the Holyhead Harpies Quidditch Team, the Anglesey Flyer proposed a fixed wizarding transportation link between London and Holyhead on Anglesey. Work began on this new line just one year after the completion of the Hogwarts line and, initially at least, things seemed to be going very well indeed. The muggles who'd been duped into laying down the line did so with commendable speed, and the wizards in charge of concealing the newly laid tracks, with all their learned experiences from the Hogwarts Line, found it a much simpler endeavour.
The great setback of the project, and the thing which laid the foundations of its final failure, was the realisation that laying a direct line through Snowdonia was simply beyond the reasonable technical capabilities of the Muggles at the time. The project stalled for months as the project managers tried everything they could to convince the muggles leading the building teams that it was reasonable and practical.
In the end, a compromise was arrived at. The Anglesey Flyer would become a literal Flyer. Between Penybontfawr and Llanberis the train would take to the air and simply fly over Snowdonia. With the compromise accepted, construction on the line began anew, and soon it was completed. Just five years after the Hogwarts Express first ran, it was time for the inaugural journey of the Anglesey Flyer and once again the great and the good of Wizarding Society were present, including the entire Holyhead Harpies team, with the single exception of their keeper, who had sadly contracted Dragonpox just days before the great day.
The Disaster of Snowdonia is one of the less known events in the Wizarding History of Great Britain, as those who remained in power afterwards felt it to be a great embarrassment, and all mention of it was struck from official sources. As a result, we must instead rely on witness testimony, of which there is understandably little. What we do know, however, is that the train was attacked by more than a dozen territorial Welsh Greens during the airborne part of its journey, and crashed into the flank of Glyder Fawr, with the loss of all but a handful of the passengers.
That disaster effectively put paid to any other rail link projects before they could so much as commence, and ensured the Hogwarts Express' singular position in the history of the British Isles