Dozens of trains carrying thousands of passengers were stranded near the Olympic host city of Sochi following a wiring malfunction on Sunday.
Sidelined passengers ended up camping outside of their trains as temperatures inside the cars soared to a sweltering 40 degrees Celsius, Gazeta.ru reported Monday.
Bloggers coined the term "hell on wheels" to describe the situation, which featured delays ranging from three to 10 hours.
At least eight people have been hospitalized due to the excessive heat, Interfax reported, citing local emergency services.
By Monday afternoon, only 21 of the 48 stranded trains remained delayed, according to state-run railroad monopoly Russian Railways.
But more trains face delays until the problem is fixed, which is expected to happen by Tuesday morning, Gazeta.ru reported, citing a company official.
The company had not announced any plans to compensate the stranded passengers by the time of publication.
The incident is believed to have been caused by record heat, which damaged the trains' wiring system, a Russian Railways spokesman said in comments carried by Interfax.
The malfunction was expected to be fixed by Tuesday morning, the spokesman said.
The Russian government invested billions of dollars into revamping the Black Sea resort town of Sochi ahead of the Winter Olympics in February.
Among other wide-ranging infrastructural improvements, the work included renovations of the railroad segment from Sochi to the nearby town of Dagomys, where the incident took place.