Amazing: Long-lost plans of Chain Bridge in Budapest have been found

A sensational discovery has been announced by the Hungarian Technical and Transportation Museum: the institution has identified the long-lost 185-year-old construction drawings of the Chain Bridge.

These documents offer a unique insight into the building of Hungary’s first permanent bridge across the Danube and shed new light on the work of the Scottish engineer Adam Clark.

Lost drawings of Chain Bridge have been found

The 25 hand-drawn sheets were created during the bridge’s construction, which began in 1839, and had been missing for more than a century and a half. The plans reveal not only the structural details of the bridge but also the process of its construction — including the timetable of the piling works and depictions of the machines and equipment used on site, writes Hungarian Technical and Transportation Museum in a Facebook post.

One particularly fascinating drawing shows that Clark originally designed four chains on each side of the bridge, although the final version was built with only two.

The rare technical drawings were first unveiled aboard the Kossuth Museum Ship, where Domonkos Schneller, Director General of the museum, highlighted that these documents could serve as invaluable sources for the scientific reconstruction of the Chain Bridge’s construction history.

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The plans will be visible for the public

Visitors will be able to view copies of the drawings at the Technical Study Collection between 1 November and 31 December, with prior registration through the museum’s research service.

The Chain Bridge was built according to the designs of William Tierney Clark and under the supervision of Adam Clark. The foundation stone was laid in 1842, and the bridge was inaugurated in November 1849 as one of the most advanced engineering achievements of its time. Clark remained in Hungary after the project’s completion and went on to lead the construction of the Buda Castle Tunnel.

Work on the tunnel began in February 1853, and by 25 October of the same year, the excavation teams working from both sides met deep beneath Castle Hill. Around two hundred workers laboured day and night, using hundreds of quintals of gunpowder. The walls and ceiling were covered with millions of tiny tiles, prompting the contemporary press to call it “the world’s largest bathroom.”

Together, the Chain Bridge and the Castle Tunnel became the symbolic axis of the Hungarian capital. The Adam Clark Square — marked by the zero kilometre stone at the bridgehead — remains the starting point of Budapest’s road network to this day.