The Signal Box at Basel Station contains electronic apparatus to regulate the signals for trains arriving at and leaving the station. The concrete structure is wrapped with copper strips, allowing a glimpse of the equipment contained within. The copper also acts as a lightning conductor to protect the sensitive equipment from a lightning strike. The concrete core is wrapped with approximately 20 cm-wide copper strips, that are twisted at certain places in order to admit daylight. Pressed between the bridge and the street, the signal box's ground plan is stipulated by a trapezoid-shaped area cut out by the railroad tracks. This shape is completed, in a gradation throughout the floor levels, into a rectangle. The project was completed in 1997.