Oslo’s T-bane system does include some Tyne and Wear-style ‘almost-metro’ lines with level crossings, but its main services are fully-separated metro lines, which are why it needs to be included here. According to the article, too, there are plans for all of the remaining sections and convert to tramways anything that can’t be upgraded. The S-tog network isn’t here simply because it’s a regional railway network rather than a local metro — look at Merseyrail in Liverpool or CityRail in Sydney for parallels in the English-speaking world.