ATHENS, Greece (AP) — Tens of thousands of people are marching in Athens and Greek cities to protest the deaths of 57 people and the serious safety deficiencies the country’s worst train disaster exposed. Clashes broke out in Athens and two other cities. Labor unions and student associations organized the rallies, while strikes halted ferries to the islands and shut down public transportation services in Athens. About 30,000 people joined the protest in the capital. A passenger train slammed into an oncoming freight train near the northern Greek town of Tempe on Feb. 28 after they were mistakenly placed on the same track. The revelations of safety gaps on Greece’s busiest rail line have put the center-right government on the defensive.