As the number of casualties from the train collision in northeast Iran on Nov. 25 climbed to 49 dead and 103 injured, 20 lawmakers have moved to sign a motion to impeach the minister of roads and urban development.

Four carriages derailed and two caught fire in the crash, which took place 250 kilometers (155 miles) east of Tehran, in the province of Semnan. The accident happened when a passenger train hit another that had stopped near Haft-khan station.

President Hassan Rouhani immediately ordered an investigation into the cause of the crash. Moreover, Supreme Leader Ayatollah Ali Khamenei in a Nov. 26 message asked Iranian officials to find the root cause of the incident and prevent any repetition of such an occurrence.

Rail transport in Iran has been the safest mode of transportation compared with air and land transport. However, the country has faced difficulties in modernizing its aged rail network due to economic sanctions imposed over its disputed nuclear program. In recent years, Iran has increased its investment in rail transport, and Rouhani's government boosted allocations for the development of the rail sector by 12.8% for the fiscal year ending March 20, 2017.