The Le Day viaduct (''viaduc du Day'') is a railway viaduct in

Vallorbe Vallorbe () is a Municipalities of Switzerland, municipality in the district of Jura-North Vaudois District, Jura-Nord Vaudois in the Cantons of Switzerland, canton of Vaud in Switzerland. History Vallorbe is first mentioned in 1139 as ''de valle ...

in the

Jura-Nord vaudois District Jura-Nord Vaudois District (, ) is a district in Vaud canton of Switzerland. Its capital is Yverdon-les-Bains. Geography Jura-Nord vaudois has an area, , of . Of this area, or 47.6% is used for agricultural purposes, while or 44.1% is forested. ...

of the Swiss

canton of Vaud Vaud ( ; , ), more formally Canton of Vaud, is one of the 26 cantons forming the Swiss Confederation. It is composed of ten districts; its capital city is Lausanne. Its coat of arms bears the motto "Liberté et patrie" on a white-green bicolou ...

. It stands near the hamlet of ''Le Day'' and crosses the

Orbe Orbe (; ; older , ; ) is a municipality in the Swiss canton of Vaud. It was the seat of the former district of Orbe and is now part of the district of Jura-Nord Vaudois. History Orbe is first mentioned about 280 as ''Urba''. In 1179, it wa ...

. This has been dammed since 1955 by the Le Day dam (''Le barrage du Day''), which lies 450 m downstream. The double-track bridge is used by

TGV Lyria TGV Lyria, owned by SNCF, yet jointly-operated by SNCF and SBB CFF FFS, is the brand name used for TGV railway lines connecting France and Switzerland. TGV Lyria is also a corporation that runs the service operated by SNCF in France and Swiss Fed ...

services between

Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...

and

Lausanne Lausanne ( , ; ; ) is the capital and largest List of towns in Switzerland, city of the Swiss French-speaking Cantons of Switzerland, canton of Vaud, in Switzerland. It is a hilly city situated on the shores of Lake Geneva, about halfway bet ...

on the Lausanne–Vallorbe line of the ''RER Vaud (Réseau express régional vaudois)'' and the line from Vallorbe to Le Pont in the

Vallée de Joux The Vallée de Joux () is a valley of the Jura Mountains mainly in the Swiss Canton of Vaud. The valley also continues into France ( Jura département) at its higher, southwestern, end. Located north of Geneva and northwest of Lausanne, its mea ...

with its extension to Le Brassus.

Lattice truss bridge (1870)

The bridge opened by the

Jougne-Eclépens Railway The Jougne-Eclépens Railway (''Chemin de fer de Jougne à Eclépens'', JE) was a railway company in Switzerland and existed from 1870 to 1876. History The ''Jougne–Eclépens'' opened a railway from a junction with the Jura Foot Railway of the ...

(''Chemin de fer de Jougne à Eclépens'', JE) in 1870 was a

lattice truss A lattice truss bridge is a form of truss bridge that uses many small, closely spaced diagonal elements forming a lattice. The design was patented in 1820 by architect Ithiel Town. Originally a means of erecting a substantial bridge from mere p ...

construction of

wrought iron Wrought iron is an iron alloy with a very low carbon content (less than 0.05%) in contrast to that of cast iron (2.1% to 4.5%), or 0.25 for low carbon "mild" steel. Wrought iron is manufactured by heating and melting high carbon cast iron in an ...

originally supported by two stone masonry pillars. Their three uneven openings created spans of 36.5 + 56.0 + 23.5 m. It was 5.0 m wide and had a height of 59 m above the valley floor. Because of heavier locomotives and trains it was strengthened in 1899 and 1900. In the 1920s, further strengthening was needed to enable

electrification Electrification is the process of powering by electricity and, in many contexts, the introduction of such power by changing over from an earlier power source. In the context of history of technology and economic development, electrification refe ...

. Extensive research resulted in its reconstruction as a massive

arch bridge An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its structural load, loads partially into a horizontal thrust restrained by the abutments at either si ...

as the cheapest solution.

Reconstruction as a stone arch bridge (1925)

The viaduct of Le Day was therefore rebuilt from 1923 to 1925 before the

Grandfey Viaduct The Grandfey-Viaduct is on the Lausanne–Bern railway, railway line from Bern to Fribourg and is one of the largest bridges in Switzerland. Location The viaduct crosses the deep and wide Saane/Sarine valley, which is cut into Molasse rock, in ...

near

Fribourg or is the capital of the Cantons of Switzerland, Swiss canton of Canton of Fribourg, Fribourg and district of Sarine (district), La Sarine. Located on both sides of the river Saane/Sarine, on the Swiss Plateau, it is a major economic, adminis ...

without interruption to traffic. It was also provided with a pedestrian walkway. During the reconstruction project carried out by the

SBB SBB may refer to: Arts and entertainment * SBB (band), a Polish progressive rock band, or their self-titled albums: ** ''SBB'' (1974 album) ** ''SBB'' (1978 album, Amiga) * Seán Bán Breathnach, also known as SBB, Irish TV personality * ''Saa ...

under the direction of Adolf Bühler, arches for the new bridge were first built into the existing openings below the iron superstructure, with the apexes of the arches reaching just below the lower girders of the lattice girders. The

falsework Falsework consists of temporary structures used in construction to support a permanent structure until its construction is sufficiently advanced to support itself. For arches, this is specifically called centering. Falsework includes temporary ...

was built by Richard Coray. Subsequently, the existing superstructure was carried by smaller supporting arches based on the pillars. Finally, sections of the iron structure were demolished and the new superstructure was built. The bridge, which had a total length of 161.25 m, was given a main span with a clear width of 44.00 m. Nine supporting arches with a clear width of 4.50 m are carried by the main arch. The arches in the different-sized side openings naturally have smaller masses. The slightly overhanging superstructure now has a total width of 8.4 m. The arches are made of natural stone because concrete from the local gravel would not have had sufficient strength and the SBB wanted to avoid a contrast with the existing pillars. Only the parts of the pillars above the footbridge, the supporting arches and the remaining superstructure were built in stamped concrete and then covered with natural stone. The walkway on the longitudinal axis of the bridge was built of reinforced concrete. The two large pillars originally stood above the streambed. Their pedestals have been in the water since the construction of the Barrage du Day.

References

Notes

Sources

* *

External links

* {{DEFAULTSORT:Le Day Viaduct Railway bridges in Switzerland Buildings and structures in the canton of Vaud 1870 establishments in Switzerland 1925 establishments in Switzerland