Eiffel Tower concession: the 20-year agreement and the machinery behind it
The Eiffel Tower concession gave Gustave Eiffel an initial operating term of 20 years. The tower had been erected for the 1889 Paris Exposition, and its future beyond the original arrangement remained uncertain. The International Telecommunication Union's history places the expiry of the site lease in 1910. The original operating term set a boundary for the attraction, while scientific work eventually helped establish a continuing purpose for the structure.
The shape of the structure made that commercial operation a demanding engineering problem. Robert M. Vogel's Smithsonian study explains that the four main legs curve inward before joining above the second platform. Elevator shafts therefore had to follow an unfamiliar route. Capacity and height of rise were already major concerns in elevator design; the changing inclination added another. The Exposition commissioners insisted on safe, reliable machinery. Visitors could walk to the lower platforms, but the expected crowds made elevators essential to the tower's operation.
Commercial operation depended on machinery that could carry large numbers of people to unfamiliar heights. Smithsonian associate curator Robert M. Vogel's study of the original elevators reproduces drawings published in engineering periodicals in 1889. The tower had three separate elevator systems, with its curving legs imposing a problem beyond a simple vertical shaft. The Otis equipment used hydraulic power and double cars carrying 40 seated passengers. Water pressure came from a reservoir on the second platform; after use, pumps returned the water to that height. The viewing platforms required an operating mechanical installation beneath them.
The French lifts in the east and west legs used another solution. Roux, Combaluzier and Lepape designed chains of short, jointed links that pushed their cars upward. Enclosing the links in conduits prevented the loaded chains from buckling. Vogel's reproduced diagrams preserve this unusual arrangement as well as the Otis machinery. The Eiffel Tower concession's business of admitting visitors was thus tied to competing engineering systems, each adapted to the shape of the iron structure.
The third system served the upper part of the tower. Léon Edoux divided the long vertical journey between the second and third platforms into two sections. Two cars, linked by cables, balanced one another while each traveled only half the distance. Passengers changed cars at an intermediate platform where the cabins met. The cylinders could then remain within the upper structure instead of extending down into the open area below the first platform. This arrangement addressed a different geometry from the curving shafts in the legs.
A contemporary reference work recorded uses beyond sightseeing. The 1911 Encyclopaedia Britannica described the tower as a 300-meter structure and gave platform heights of 57, 115 and 276 meters. It noted meteorological observations alongside the views enjoyed by visitors. Its description places scientific work among the tower's recognized activities near the end of the original operating period. Observation platforms were also working locations, and the structure's height could serve both the paying public and people taking measurements above the city.
An instrument recognized in the American Society of Mechanical Engineers' landmark record gives a more tangible example of that research. In 1903, Eiffel suspended a vertical cable from the tower's second level and dropped objects of different shapes along it. The apparatus measured air resistance during the fall and recorded the result on a chart inside the machine. Over the next three years he tested about 40 shapes. The tower supplied a long, controlled descent, while the recording mechanism converted a brief fall into measurements that could be compared across repeated trials.
Longer experiments required a different arrangement. Eiffel built a wind tunnel beside the tower in 1909, using power from its generator. Air now moved past fixed objects, including shapes already examined in the falling tests. Comparisons supported the equivalence of drag measured with a moving body in still air and a stationary body in moving air. Complete aircraft models could also be tested. ASME's record traces the work onward to the Auteuil laboratory opened in 1912 and identifies the surviving drop-test machine there. The experimental apparatus outlasted its original installation on the tower.
Wireless communication supplied another use as the Eiffel Tower concession approached its 1910 boundary. In its later institutional history, the International Telecommunication Union credits the French Army's Engineering Corps under Captain Gustave Ferrié with developing radio experiments from the structure. By 1908, transmissions reached 6,000 kilometers. A permanent station beneath the site strengthened the military installation. Radio gave the height of the tower a practical communications role, while the station below made that role part of an enduring system of equipment and personnel.
The ITU describes this military radio work as central to the tower's preservation when the original site lease was due to expire. That is a later explanation of its survival, alongside the expiry of the original operating term. The radio service also developed a public audience: Radio Tour Eiffel carried news and concert programs until 1940.
- International Telecommunication Union, France and ITU: Broadcasting innovation from the Eiffel Tower, 14 May 2025, original 20-year term and 1910 lease expiry — www.itu.int
- Robert M. Vogel, Elevator Systems of the Eiffel Tower, 1889, Smithsonian Museum of History and Technology paper 19, including contemporary engineering drawings; Project Gutenberg — www.gutenberg.org
- Encyclopaedia Britannica (1911), Eiffel Tower: contemporary description of platforms and meteorological use; Wikisource — en.wikisource.org
- American Society of Mechanical Engineers, landmark 237: Eiffel Drop Test Machine and Wind Tunnel — www.asme.org