Russian Railways Company (RZD) has named preliminary reason for the derailing of four passenger carriages on Saturday.
"According to preliminary reports, the reason of derailing of four carriages of a passenger train was unauthorised interference of unidentified persons in work of the railway transport," the company's statement reads.

Investigators and prosecutors continue working at the scene.

A railway repairing worker has confirmed the accident with the passenger train in Mordovia was caused by stolen rail fixators.

"Yes, correct, elements of fixing the upper layer of the rail is stolen," a specialist working at the scene told TASS on Saturday. He said several fixings along about 30 metres had been stolen, which caused the rail disorder.

Four carriages derailed at 10:37a.m. on Saturday. The train was going from Yekaterinburg (Urals) to Adler (North Caucasus).

No victims have been reported.