Unidentified men blew up a portion of the Zahidan-Quetta rail line in Balochistan on Thursday, officials said on Thursday. Wednesday's blast was the third in a month to hit the line from Quetta to Zahidan in Iran. A scheduled fortnightly train between the two cities left early on Thursday after engineers worked overnight to repair the track, Pakistan Railways Chief Controller Mohammad Shoaib said. "Terrorists hit the line at Nushki, about 150 kilometres west of Quetta on Wednesday," he said. An explosion also damaged a portion of the Dera Ghazi Khan-Kashmor rail line near DG Khan on Thursday, suspending rail traffic, Geo news channel reported. Unidentified men had planted a bomb a kilometre away from the Kot Chatha Railway Station near DG Khan, which went off in the evening. Railways Police, Punjab Police and a bomb disposal squad rushed to the scene, the report said, adding that no train was passing by at the time of the explosion. DG Khan District Police Officer Salman Chaudhry told Geo that the terrorists would be arrested soon. Meanwhile, unidentified men blew up a PTCL microwave transmission tower at Ahmedwal near Nushki early on Thursday. The tower was situated close to the rail line. The blast severed communication links between Ahmedwal and the rest of the country. Separately, four homemade bombs exploded in Balochistan, damaging a wall and shattering windows but causing no injuries, police said on Thursday. The first bomb went off outside the home of a Railways Police official late on Wednesday in Quetta, damaging a wall and shattering windows of several homes, said Qazi Wahid, a senior police official.