Twisted pair was invented shortly after the telephone line, see https://en.wikipedia.org/wiki/Twisted_pair#History https://en.wikipedia.org/wiki/Twisted_pair#Hi

Twisted pair was invented shortly after the telephone line, see https://en.wikipedia.org/wiki/Twisted_pair#History https://en.wikipedia.org/wiki/Twisted_pair#History and the image there: the wires were still separated by distance. At least in Europe, however, many places still used single-wire connections with return through earth for local lines during the first few decades. Not sure about Stockholm. Anyway, I am guessing insulation was too expensive.