220 kV Transmission Line Innertkirchen – Mettlen, Replacement of Masts 87 + 91

Masts 87 and 91/TR1490 are located in the Giswil – Glaubenbergpass region in an area which is well-known for landslides. The masts had shifted and tilted as a result of movement on the slope and were therefore replaced.

Particular challenges included:

  • A challenging time schedule due to the demands of the construction timeframe and the short isolation time of the power circuits
  • Difficult on-site conditions and exposed location of the construction site
  • Complicated access (transportation of materials by helicopter, temporary access tracks etc.)
  • Live overhead lines
  • Environmental protection considerations and environmental sensitivity of the area

Main Data

Mast 87 / TR 1490 (support mast)

  • Height: 36.70m, distance between the founda-tions: 6.30m

Mast 91 / TR 1490 (guyed mast)

  • Height: 38.90m, distance between the founda-tions: 7.70m
  • Total weight of the mast: 10,380 kg


Swissgrid AG


IUB Engineering AG

Construction period


Construction costs

CHF 750,000

Scope of services

On-site construction supervision / construction management, commissioning