Why do Swiss trains and trams get so hot during the summer?

With the weather in Switzerland getting hotter and hotter, many passengers on Swiss public transport have started to complain about sky-high temperatures on board buses, trams and trains. Now, the Zurich Transport Authority (VBZ) and Swiss Federal Railways (SBB) have told Watson that not only are the complaints valid, but there is a very good - and stereotypically Swiss - reason for not lowering the thermostat.

SBB and VBZ admit to not cooling services

In statements given to Watson, SBB and VBZ admitted that they do not cool their vehicles down much during the summer. As a result, temperatures inside transport services across Swiss cities are usually only a few degrees colder than outside.

Flooded with messages from angry, and most likely sweaty commuters, Watson asked the companies why they deliberately choose to not cool their trams, trains and buses. Their response was typically Swiss: they said the policy is not to help achieve their goals of climate neutrality or save energy, but instead is designed to protect the health of passengers.

Hot trains meant to combat temperature shocks, says VBZ

In the statement, VBZ explained that if they were to cool their vehicles down as much as they can - likely down to around 20 degrees celsius - it leaves passengers at risk of “temperature shock”, which can, allegedly, lead to an entzündung (infection). Temperature shock is caused when people move quickly from high to low temperatures or vice versa, like moving from the hot outdoors into a well-air-conditioned building or vehicle and back, for example.

While it may seem silly, especially to people from countries where air conditioning is commonplace, Dr John Whyte, chief medical officer for WebMD, told the American media back in February that sudden changes in temperature can make people feel ill. He explained that the body perceives sudden changes in the climate as a sign of stress, making people more susceptible to illness - headaches, fever, fatigue, runny nose and watery eyes are all known symptoms.

Workers at VBZ unable to move the thermostat

Therefore, perhaps being inspired by every Swiss person whose last item of clothing to leave their body is a scarf, to help avoid pesky entzündungs, VBZ only cools the inside of their vehicles by a few degrees compared to outside temperatures - even when the mercury goes above 30. However, they do take steps to lower the humidity. 

Workers at the company looking to turn the thermostat down can’t as the cooling systems are permanently set to react to outside temperatures. Luckily, the majority of VBZ services still have some form of air conditioning - with the exception of some trams used during rush hour.

Temperature shock measures also apply to Swiss trains

Speaking to Watson, SBB revealed that they play a little more fast and loose with the temperature in trains, with thermostats set to between three and seven degrees below outdoor temperatures. They added that while their policy is also designed to avoid “temperature shocks”, reductions in energy consumption are a welcome bonus.