[belorn]

One of the heaviest rail, if not the heaviest rail in Europe, is a 500km combined freight and passenger rail that goes between Sweden and Norway (The Iron Ore Line). It alone carries more than the combined weight of all rail freight transportation in Norway, and close to 50% of all rail freight transportation in Sweden. It also happens to be one of the worlds oldest railways, built in 1888.

The biggest issue is speed. The maximum speed is just slightly above that of maximum highway speed, with freight speed limited to less than half of that.

[dagw]

That line is fantastic for freight (unless they've derailed an ore train again...), but the passenger service it offers would feel right at home in the US when it comes to both speed and number of departures. The passenger service to Norway leaves 0-2 times a day

[generj]

The line between Kiruna and Narvik is so beautiful I’m not sure why you’d want it to go faster. The speed is heavily dictated by the number of tunnels and turns due to mountainous terrain. It couldn’t be much faster without very expensive kilometer long tunnels.

Population density in North Sweden and Norway is low enough that a few times a day is probably sufficient for most local travel. I haven’t been during peak tourist seasons when that number of trains might not be enough.

A fun fact is that since the ore trains travel mostly downhill, braking generates enough electricity that the ore empty trains can return to Kiruna effectively energy free.

[anamax]

> The line between Kiruna and Narvik is so beautiful I’m not sure why you’d want it to go faster.

That makes it a tourist line, not a transit line.

There's nothing wrong with tourism, but it isn't transit.