I worked on Train at the end of the project, about 3-4 weeks. I was responsible for the main train scripting system and the first action bubble (first valley and station). I did write up a page on my website talking about all the things I did with the map. I was mostly involved in the AI combat (pacing) systems and the main train script, it took forever to test it correctly.
I thought the map was cool because it took a traditional game element (rail shooter) and turned it into a sandbox element. (Player freedom) Unfortunately people either loved or hated the level and that was often linked to how they play games. People often expect something to be the same in every game and when it is different, they sadly (for them) forget to try new ways to play. Some reviews and community comments did not even realise you could get off the train and play the level at your own pace, oh well. :/
My postmortem review:
http://www.simonoc.com/pages/design/games_pro/warhead_train.htm
I even put an easter egg in the first valley across the lake behind the tree's. It was sort of my signature for which levels I worked on.