The Swedish train system is notorious for its lack of reliability and continuous delays. Anybody who travels by train in Sweden has probably called it stupid, or worse, in anger or frustration. However, this is not where the Swedish expression (you are) ‘more stupid than the train’ comes from.
To understand the origin of this expression, we have to travel to my home country of England and to the end of the Industrial Revolution. In the 1800’s the rail industry was booming and in 1856 Sweden imported a train from the UK, pictured above.
A Swedish tradition is to give names to trains, and this particular train was christened ‘Prince August’ after King Oskar I’s youngest son. Prince August was well-known across the country for not being the brightest light in the Christmas tree. His weak intellect was well referred to in stories of the time. This was a period in history, however, when open criticism of the Royal family borded upon treason. So, the people created an expression – more stupid than the train – to describe somebody’s idiocy while at the same time referring ‘discretely’ to the royal fool by referencing the train of the same name.
This tradition of naming trains, and train carriages, still exists in Sweden today. Only this morning I travelled in a carriage called Pippi, but I’m afraid it wasn’t much of an adventure. Here is a list of all the carriage names on the Stockholm underground – see if your is there!
Watching the Swedes 
When I was around seven years old my grandfather used the expression and told me I was more stupid than the train. Dum = stupid/mean. My quick, and actually quite clever respons was “But there are ‘snälltåg’ as well”, where snäll = nice/friendly and “snälltåg” comes from the german Schnellzug = high speed train.