I am just in the process of re-listening to THS read by Michael Jayston, and the opening passage with High Haven is, in my opinion, one of the best openings to a novel in the English language.
I've been to a pride today in Berlin...guess the temporary tattoo on my arm decided to go for "Prid of Ankh-Morpork".
tldr: Why is there not enough AC in public transport: costs, age of stock, time to replace, and politics.
After seeing a number of posts, some with quite ridiculous language, over the last week discussing the status of air conditioning on the public transport system in Berlin, I thought I would write a bit of an explanation.
Before I start, first of all I would like to say that I work as an engineer/project manager in major infrastructure projects, but not public transport. Also, I am a daily user of public transport, and firmly believe in it as both a concept, and a working system. Furthermore, I also suffer in this heat, and hate getting into a train that has no AC. I have no agenda in terms of shaming people or making them feel bad. Finally, climate change is real.
When it comes to infrastructure, the big drivers are cost and technical capability, and a balance between them; it is just not cost effective to design and build a system which can 100% cope with every possibility that might be seen during the lifetime of the project. In defining the technical requirements of a project, you will consider the risks and likelihoods, and then this will assist in specifying the requirements.
Therefore, when BVG or DB need to buy new trains, one of the things they will consider is the average, high and low temperatures seen, and then will consider the most cost effective way to deal with them.
As the official website of Berlin states, "Comparing the period from 1991 to 2020 with that from 1971 to 2000, the average number of summer days increased from 39 to 49 per year and the number of hot days from 8 to 13."¹ in addition, as stated by BVG, "...over 1,200 vehicles are in operation on nine subway lines, connecting 175 stations over a distance of around 155 kilometers."² Of those 1200 vehicles, 208 were built between 1974 and 1994³, 276 were built between 1994 and 2002⁴, and 96 between 1999 and 2006⁵. That means that 48% of the trains were designed and ordered before 2000, when the current regular extremes of temperatures were not foreseen at all.
Additionally, BVG has looked in to fitting the U-bahn with AC but decided against it, noting "the limited space between the train and the tunnel ceiling, the high costs of modifications to the tunnel system, and the energy consumption. Furthermore, passengers only travel on the subway for an average of about 13 minutes."⁶
As well as this prohibitive cost of changing the tunnel system, the cost of a new U-bahn train is roughly €12,000,000 (€2,000,000 per car).⁷ These trains are expensive , highly technical machines, which take years to order and build. Any competent company would not throw away old, working stock that was unsuitable for a few days a year, and even if they did, there would be no replacement for a number of years.
For the S-Bahn, it is a similar story, without some of the tunnel restrictions. Approximately a quarter of the S-Bahn trains are currently equipped with AC and that is growing, but these units come at a cost of around €3,000,000 per car. Again, DB could not be considered a competent company if they threw away working trains for only a few bad days a year.
Finally, there is politics. Here I do not talk about right versus left, but rather how important AC in public transport, along with other spaces, is, when we come to our elections. Essentially, politicians decide on the nationwide, state and local levels how we invest, or indeed don't invest in our public transport. If a politician were to stand on a major policy point of AC on all trains, then they would likely not get elected, or if they did, it would be for another policy, except in the extremely unusual, and lucky for them, point of having an extreme heat wave across the entire period of the election, from starting to run to declaring the winner.
So, when you are fed up of the heat, stepping in to a train and finding no AC, and wonder why, the simple answers are: costs, age of stock, time to replace, and politics.