The article is about the worlds first hydrogen train in Germany. Hydrogen trains emit only steam and oxygen. That's why they are very eco-friendly. Many people find them as one of the best way to reduce the effect of global warning.
However, I'm concerned about their safety. Because hydorogen is extremely explosive gas.
Once it explodes in a tunnnel, for examples, no one can rescue passengers and crews. And also initial cost is quite expensive when they are built. I guess It will take long time until they become more common in Europe.