At least 21 people died in eastern Iran on Wednesday when a train derailed while travelling on a route undergoing construction work, state media reported. About 90 other passengers were injured in the accident near the city of Tabas, according to an Iranian Red Crescent tally of casualties. The train was travelling between the holy city of Mashhad and the desert town of Yazd when eight of 11 carriages derailed some 50 kilometres outside Tabas, the Khorasan provincial governor’s office said. Transport Minister Rostam Ghassemi, who went to the scene of the accident, said an excavator played a ro…