You speak my mind. Trains are (with very good reason) always considered a clean way of travelling, they are many times less harmful than each passenger driving or flying instead of taking the train. But diesel train emissions seem to have escaped notice, maybe people don't notice that there simply aren't electric trains in the Scottish highlands, or large parts of Wales. but diesel trains are a threat to the environment, and don't seem very regulated. I am sorry if this is a bit off topic. Continued use of HSTs is really good, making use of trains that were built to last 40 something years ago is so much better than scrapping them and building new ones, but their engines are far from clean, and that is definitely an issue that needs to be urgently addressed.