Arch Wall takes one of the tallest and least featured parts of the Troll wall and, at the time of the FA (Hugh Drummond, Ed Ward-Drummond 1972), it was the most difficult big wall route in the world with pitches up to A4+. This also says a lot about the possibilities to place gear - seriously bad. There are a number of really difficult multi-pitch routes in Norway, but this one is different. Where the other routes typically follows distinct granite lines, this is not the case here, making the climbing a significantly more serious undertaking, featuring run-outs of 15m where you have to rely on "birdbeaks", tiny hooks placed in thin seams.
Arch Wall was one of the last great lines, but was viewed by most as an almost utopian project to climb free, being really tall, almost always wet, loose with bad pro and few holds...
If anyone could do it however, it was Sindre Sæther, a strong climber with a strong head who has redpointed 8c+ and onsighted 8b, as well as having done several serious multi-pitches on the Troll wall.
Source: Drammensgranitt (Norwegian)