N. Kósa Judit - Szablyár Péter: Underground Pest - Our Budapest (Budapest, 2002)

A tunnel for cables under the Danube

■ The cable tunnel

Work started in 1941. The location of the starting shaft on either bank was assigned to within 120 metres south of the Southern Railway Bridge. The so- called caisson method, a procedure involving overpressure and also used for the construction of the underground railway later, was applied with the drilling. Earth was removed from the tunnel using mining technology and manual labour. The tunnel was then walled around with a double lining of bricks. Water leaking in was collected at the bottom of the tunnel, from where it was conducted to sumps at the starting shafts and then pumped to the surface. When the two half-tunnels were ready, the brick walling was plastered over and lined with a 20-centimetre thick concrete tube. The space between the two structures was filled with mortar. Within the tunnel the cables were laid on concrete shelves whose width varied between 15 and 30 centimetres, leaving an 80-centimetre wide and 185-centimetre high monitoring and maintenance passage. The tunnel was lit with 95 waterproof lights, and ventilation was pro6