Before the construction of the high speed line connecting Brussels to Paris, the Viaduct of Moresnet was listed as Belgium's longest rail bridge.

The Montzen line, of which the Geul Valley bridge is part, was designed for military transport and has subsequently been used as a freight route.

It was part of the so-called Montzen line designed to provide an alternative relatively unimpeded rail route for the speedy transfer of supplies to the western front across the high ground marking the pre-war border between Germany and Belgium.

The old frontier crossing at Herbesthal railway station itself was the channel through which more than 70,000 Belgian forced labourers passed, and it also became the unintended home and nursing centre for thousands of stranded war casualties.

Work on the Geul Valley bridge started early in 1915 and was completed in October 1916, although the full "Montzen line" rail route opened for through traffic only in 1917.

The companies involved in the construction were, principally, Dyckerhoff & Widmann, MAN Werk Gustavsburg Grün & Bilfinger and Gutehoffnungshütte [de].

The rail tracks themselves are mounted not directly on the concrete, but embedded in a gravel ballast bed in order to protect the structure from vibration and support noise reduction objectives.

This exercise was undertaken, two deck-sections at a time, at approximately eight weekly intervals during a weekend "window" when the line was closed to traffic.

[1] After the renewal of the bridge-deck had been completed, plans were implemented in 2008 to electrify the final 7 km (4 miles) of line, being the section between Montzen [fr] and the Gemmenich Tunnel [de], which includes the Geul Valley bridge.