Among my memorable anecdotes from my construction projects: piloting and installing "umbrella arches": The Tartaiguille Tunnel is a French railway tunnel on the LGV Méditerranée high-speed line. It is located in the municipalities of La Roche-sur-Grane and Roynac, in the Drôme department, in the Auvergne-Rhône-Alpes region. It was opened in 2001 by SNCF. The umbrella arch installations were carried out using a 640 SM surveyor and Topo6tem software running on an HP200LX. The device is automatically controlled, as demonstrated by the example of a GEODIMETER SM540 installed on a Baechler console in 1998.