I hope you’re sitting down for this. Perhaps you’d even like to prepare yourself by taking a few deep breaths.
I’d like to recommend that you read this article from The Guardian. There. I’ve said it.
Although my feelings about said newspaper are generally well documented, I have to say that George Monbiot has written a particularly good article about the environmental impact of rail travel. As you may know, this will be my area of research once I’ve got some exams out of the way, and it looks like there could be a few surprises and some tough decisions to be made.