Train services throughout Spain were suddenly slowed on Friday when thousands of rail workers went on strike to protest the government’s plans to restructure the sector.

Service was minimal in most cities, frustrating passengers, especially those who tried to purchase tickets at rail stations where counters were closed.

Officials from the CCOO labor union reported that 90 percent of workers from Renfe, state-owned Administrator of Railroad Infrastructure (Adif) and Feve, which runs lines in the northern regions, joined the strike. Public Works Ministry officials said that the strike may have cost the government up to four million euros. Rafael Catalá, secretary of state for infrastructure, said that the money lost mostly stemmed from passengers who took alternative routes. Rail workers are protesting plans to open the sector to private competitors and eliminate state-owned Feve.

Another strike has been announced for September 17.