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MOSCOW, June 25 (Reuters) - Hundreds of passengers were evacuated from a train on Moscow's underground railway on Wednesday after a derailment blocked a busy line, leading to huge crowds on other routes.

The Serpukhovsko-Timiryazevskaya metro line was shut down during the rush hour after four train carriages derailed in a tunnel between two stations in a northern Moscow suburb. There were no fatalities.

"A stretch of rail about 1.5 metres long cracked," Pyotr Biryukov, a deputy Moscow mayor, told the Vesti-24 television channel. He said 10 people with high blood pressure had asked for first aid.

"All in all, around 800 passengers were evacuated," Russian agencies quoted Yevgeny Bobylev, a spokesman for Moscow's emergency service, as saying.

Earlier, Russian media had reported the evacuation was caused by a fire, but a metro spokesman denied there had been a blaze.

A Reuters reporter said a busy motorway north of Moscow was congested, with scores of people trying to hire cars to get home after work.

Vesti-24 showed amateur mobile phone footage from another line, with huge crowds of people elbowing their way to trains and escalators.

One person was hospitalised. Several others suffered from bruises and dislocations caused by emergency braking. (Reporting by Dmitry Solovyov; Editing by Giles Elgood)

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