Following the worst accident in the Moscow metro's 80-year history, Mayor Sergei Sobyanin fired the head of the metro's management company, Ivan Besedin, on Tuesday.
"This tragedy crossed out all the great work that had been done in the metro in recent years," Sobyanin said at a City Hall meeting, Interfax reported.
Sobyanin appointed Dmitry Pegov, former director of Russian Railways' high-speed rail department, as Besedin's replacement.
The goal of the new metro head will be to restore Muscovites' trust in the system and "prove that the metro is the safest mode of transportation," the mayor said.
Three metro cars slid off the track between the Slavyansky Bulvar and Park Pobedy metro stations on the Dark Blue Line during rush hour last week, killing about two dozen people and injuring more than a hundred.
Investigators have said that the incident was caused by improper work on a railway switch, installed recently before the crash as part of the metro's large-scale expansion program.
Two rail technicians responsible for overseeing the work on the railway switch have been arrested and now face up to 10 years in prison. Two more suspects, a deputy head of the metro's rail maintenance service and a production director of one of the metro's subcontractors, were detained on Monday.
Besedin worked as head of the metro for about three years. He was appointed to the post in February 2011, replacing Dmitry Gayev, who had managed the system since 1995.