Thousands of commuters were affected by massive disruptions to train traffic in the Stockholm area and the Östergötland region on Monday afternoon and evening.
All train traffic between Mjölby and Norrköping in south-central Sweden stopped at around 4pm on Monday, after young people were reported to have thrown branches on to power lines at the railway tracks from a flyover bridge in Linköping.
Police in Östergötland told Swedish news agency TT that they had not yet found a suspect, but were investigating sabotage.
“We are collecting information,” press spokesman Thomas Agnevik said.
The disruption affected trains from Stockholm to Malmö as well as local commuter trains in Östergötland. One of the tracks opened a few hours after the incident, but the second track remained shut off until 11.30pm.
Shortly before 4pm on Monday, a signalling fault in Solna created total disruption to all rail traffic north of Stockholm, affecting trains between Stockholm and Uppsala as well as commuter trains between Stockholm and Märsta/Uppsala and the airport express to Arlanda.
The fault was repaired by 11pm. A total of 15,000 passengers were believed to have been affected.
“We have ordered buses to Solna, but they're not enough,” said Anders Edgren at state-owned train operator SJ's press office to TT.
The Swedish government announced plans in their spring budget for a billion kronor railway revamp earlier in April. Ministers want to invest 620 million kronor ($72m) in 2015 and thereafter 1.24 billion a year until 2018 to put an end to delays and train cancellations which have plagued Swedish rail travellers in recent years.
Last week, commuters in Stockholm were left stranded at rush hour after a cable caught fire at one of the capital's railway stations, only days after more than a dozen trains came to a halt when an electric wire was torn down in southern parts of the capital.