The following requirements of the client had to be fulfilled for the materials supplying unit to the underground substation:
- For loading, the crab trolley must be able to leave the building of the supply shaft . The doors to the building of the supply shaft must be lockable, and may not be penetrated.
- The trolley can be driven electrically along the total length.
- The hook path has to extend down to a depth of 18,5 m.
- From 3 levels of different heights safe operation of the crane is required.
- The crane has to be approved by the safety authorities, before commissioning.