TOKYO >> Railway companies are stepping up their efforts to keep things cool in response to a series of passengers suffering heatstroke in trains and stations. With the Tokyo Olympics and Paralympics set for next summer, companies operating in the Tokyo metropolitan area are using cutting-edge technology — such as self-adjusting air conditioners — near busy stations. They’re also employing special window glass to shut out ultraviolet rays.

On a recent morning, a crowded train on the JR Yamanote Line was hot and humid. But as it approached Ikebukuro, one of Tokyo’s biggest terminal stations, the car gradually cooled.

Three years ago, East Japan Railway Co. (JR East) studied extensive data that tracked passenger numbers during various times of the day and in various zones. Based on its findings, the company introduced train cars that automatically lowered AC temperatures prior to arrival at busy stations.

The trains were also programmed to adjust temperatures based on the combined weight of passengers, reflected by the amount of pressure exerted on car floors.

Leading railway companies, including Tokyo Metro Co., Odakyu Electric Railway Co. and Hankyu Corp. have installed similar systems.

Some trains, including those of JR East and Seibu Railway Co., are equipped with glass that keep cars cool by absorbing ultraviolet and infrared rays.

Without these measures, riders could succumb to the heat, and that potentially leads to added trouble.

Heatstroke among passengers can also cause delays in train schedules. And if trains stops are lengthy, more passengers could suffer health problems.

“More passengers become sick in crowded trains in summer because heat and odors stay inside the trains,” said one train official.

According to the Tokyo Fire Department, from June to September last year, 346 people were sent to the hospital from stations and trains with apparent heatstroke. That was three times more people than the previous year.

During the Tokyo Olympics and Paralympics next summer, stations near venues and major stations are expected to be extremely crowded. To prepare, JR East has set up a trial with partnering Tokyo hospitals in which ill riders at busy stations are diagnosed by videophone.

The company will assess the results of the trial to respond to the influx of riders during the Tokyo Olympics and Paralympics.

But however prepared railway companies are, riders are advised to care for themselves properly when riding crowded trains during hot months.

“Some people could develop symptoms of heatstroke, such as dizziness and nausea, even though they’re on trains not exposed to direct sunlight,” said Toshiki Mano, a physician and professor at Chuo University. “It’s necessary to drink fluids frequently when traveling, and to take other measures such as changing trains depending on (crowd) congestion and one’s (own) health condition.”