If you live outside of urban centres (which have their own public transport system), you have likely seen yellow post buses — 2,400 vehicles covering a network of 936 lines that span almost 17,000 kilometres of country roads, no matter how narrow and winding.

In fact, if you want to go to the mountains but don’t feel like driving, a PostBus will bring you all the way up, practically to the top.

And you should not be concerned that you will have to sit on top of a stack of mail — these days, the buses transport passengers only.

But it hasn’t always been this way.

The first buses took to the roads in 1849, replacing horse-drawn coach services that were used to deliver mail until then. However, the early buses encountered — figuratively and literally — quite a few bumps along the way.

According to an article on House of Switzerland site, ran by the  Federal Department of Foreign Affairs (FDFA), “the first official PostBus journey took place between Bern and Detligen in 1906. But the buses used up a lot of fuel and had numerous technical issues”.

As more Alpine passes were dug after World War I, including Simplon, Grimsel, Furka, St. Bernard and Oberalp, 40 military trucks were converted into  post buses, gradually extending the  network of postal lines throughout Switzerland.

“PostBus turned from a simple public transport service to a veritable social institution, linking rural folk with the modern life of the towns and cities”, the FDFA article says.

“Not only did it venture into remote and mountainous parts, PostBus also operated in Switzerland’s central plain in order to serve the villages and towns”.

In those days though, “buses weren’t just transporting school kids, villagers and tourists – they also had letters, parcels, milk cans, fridges and even chickens on board”.

You know it’s a post bus when…

Unlike ‘regular’ public buses, postal buses have two unique features: they are bright yellow and have a distinctive three-tone horn.

While in the first half of the 20th century post buses sported different hues, in 1959 they were all painted ‘Swiss Post yellow’, as the colour is officially known.

The next milestone came in 2002, when Swiss Post’s trademark yellow colour was registered and granted trademark protection.

What about the horn?

As the narrow Alpine roads were (and still are) used not only by post buses but also by an ever-growing number of private cars, accidents were frequent. So the Swiss Post decided that its drivers should sound a horn to warn other road users about blind spots.

READ MORE: Why Switzerland’s roads are among the safest in the world

But the post bus’ three-tone horn is distinct and different from the way other horns sound. It is more melodious, and for a good reason: it comes, appropriately enough, from the overture of Rossini’s opera “William Tell”.

You can hear the horn, and see when it is being used, here:

Over the years, post buses have evolved, taking new forms.

In 2016, an electric shuttle pilot project known as SmartShuttle was launched in Sion, Valais.

The driverless vehicles now include on-demand services, allowing travellers to book a shuttle free of charge for the route they want. 

READ MORE: Postbus launches new open-top coach

Not always a smooth ride

Scandals sometimes befall cultural icons and post bus is no different. Fortunately, it happened only once in its long history.

It was revealed in 2018 that post bus used accounting tricks to illegally obtain at least 90 million francs in state subsidies for the operation of its regional transport services.

READ MORE: Swiss PostBus scandal: ‘It’s much more than the money. It’s a cultural shock’

But this one bump in the road has not permanently tarnished the image of Switzerland’s yellow, three-tone-horned bus.