[1] The tunnel has a minimum curve radius of 400 meters (1,300 ft) and a gradient of 1.0 percent climbing southwards.

Through Bekkelaget it originally ran in a day section along a right-of-way slightly elevated above Mosseveien.

[3] NSB was after the slide of the opinion that the railway could be repaired easily and that with investments of 700,000 Norwegian kroner the area could be secured to allow trains to pass on the new shelf.

[2] The compromise involved that Oslo Municipality and Akershus County Road Administration would pay for the costs exceeding those which had run it the line had been built along the former right-of-way.

The new tunnel received a minimum curve radius of 400 meters (1,300 ft), less than the former line.

Local residents protested and NSB agreed to build a new halt at the southern entrance of the tunnel, 460 meters (1,510 ft) south of the former station.

The porous rock meant that there was a need to repeatedly build support columns, slowing progress.

A 180-meter (590 ft) cutting was made on the south side of the tunnel, to make a place for the station.

A road bridge was built over the northern entrance to allow Mosseveien to pass over, and when it was completed the tracks and wiring could be installed.