According to Clause 3.6 of the “State Sanitary Rules and Standards for the Operation of Railway Rolling Stock for Passenger Transportation”, during the journey, as well as when the train is being prepared for passenger boarding in winter and during transitional seasons, the air temperature in all types of carriages should be maintained at +20 °C ± 2 °C. In summer, the temperature should be +24 °C ± 2 °C (only in carriages equipped with air conditioning).
In carriages equipped with automatic ventilation and air-conditioning systems, the ventilation system must switch on automatically depending on the air temperature inside the carriage.