Ok not super exciting Duke4 news, but any news is good news..right? Level designer Charlie Wiederhold replied to someone who was complaining about a physics flaw in the UT engine in this thread (basically not liking how bullets are fired). Here's what Charlie had to say:

There is no way that a current game can properly track and adjust for hitscan weapons based on things like this. There simply isn't the horsepower yet. Imagine a guy out there with a machinegun firing 10 rounds a second. Now imagine 8 of those guys out there. It won't work. There is a reason why bullet weapons are "hitscans" as someone already described. It never travels, it simply arrives instantly where it should. Even this minor minor calculation can cause problems if a lot of people are firing hitscan weapons around each other.

And yes, the train isn't moving either, it's the same trick that was done in Blood, Sin, Blood 2, and now UT (as well as other games I'd imagine). You work with what you've got. Someday we'll have a train traveling through the countryside, but for now that's the best you can accomplish and actually be able to play on. It may be cheap, but since almost everything in the games you play are hacks/illusions... it's not a big deal :)