Striking labor unions have brought transport services to a standstill to protest the deaths of 57 people in Greece’s worst ever train disaster that has exposed major safety deficiencies. The strikes Wednesday halted ferries to the islands and disrupted public transport in Athens, where thousands were expected to attend union-organized protests against the government. Prime Minister Kyriakos Mitsotakis, who faces elections before the summer, has pledged full cooperation with a judicial inquiry into the deadly Feb. 28 collision. But revelations of serious security gaps on Greece’s busiest rail line have thrown his center-right government onto the defensive. The passenger train slammed into an oncoming freight carrier mistakenly placed on the same track, killing dozens of passengers — including many university students — in burning rail cars. At funerals held around Greece, the victims were buried in closed white caskets following a harrowing identification process. Senior officials from a European Union railway agency are expected in Athens Wednesday as part of promised assistance from the bloc to help Greece improve network safety.