Core Viewpoint - The article discusses the regulations regarding the carrying of summer cooling items on trains during the peak travel season, emphasizing safety and compliance with transport rules [1][3]. Group 1: Allowed Items - Passengers can carry small electric fans as long as they do not disturb others, as they are considered ordinary electrical appliances [3]. - Sealed ice packs for storing perishable food and medications are permitted, provided they are intact and leak-free [5]. - Non-pressurized sunscreen products like creams and lotions can be carried without restrictions [7]. Group 2: Restricted Items - Sunscreen sprays and similar aerosol products are limited to one bottle per person, with a maximum capacity of 150 milliliters, and the total for similar products cannot exceed 600 milliliters [7]. - Flammable items such as flower dew and perfumes are restricted to a maximum of 100 milliliters per bottle, with only one bottle allowed per person [7]. - Cosmetics containing flammable substances like alcohol and ether are prohibited, while disinfectant wipes with 75% alcohol content are allowed [9]. Group 3: Additional Information - Passengers uncertain about what items can be carried are encouraged to check the railway's official app or website, or contact customer service for clarification [9]. - Items not allowed on board can be shipped via express delivery services available at many train stations [9].

Group 1 - High temperatures in closed car spaces can exceed 80℃, leading to potential explosions and fires from common items like lighters, perfumes, and power banks [1][5] - A simulation by firefighters showed that lighters can explode within 2 minutes at high temperatures due to the expansion of liquid butane [4][5] - Perfume bottles can eject their nozzles after 20 minutes in high heat, as alcohol inside vaporizes and increases pressure [4][6] Group 2 - Items like sunscreen and aerosol sprays can also explode in high temperatures due to increased internal pressure [6] - A magnifying glass can ignite paper within 40 minutes by focusing sunlight, similar to how other round objects can act as lenses [8] - Power banks can reach temperatures of 137℃ after 50 minutes in a hot car, posing risks of swelling and potential fires, especially if they contain substandard batteries [11] Group 3 - Cooling sprays can cause explosive reactions if used improperly near open flames, as demonstrated in a test where a fire ignited after spraying the product in a closed car [13] - Firefighters advise against leaving items like lighters, perfumes, and power banks in cars during summer to prevent accidents [13]