I'm writing an adventure in which the PCs may attempt to smuggle something valuable out of Seattle on an automated hazardous waste train (run by Renraku, but with space rented to the other corps) that leads to a facility near the border with the Salishe-Shidhe. They'll be ambushed by other runners, and a three way battle will develop between the two groups and anything that gets unleashed in the process. I want to have a lot of interesting stuff on the train - any ideas?
I've already decided to include some experimental "smart nano-lubricant" that's both highly toxic and seeks out the sites of greatest friction, and can't tell the difference between a hinge and an elbow joint, some experimental weapon salve (that may or may not work -- basically, it's an old hermetic magic potion that heals wounds if placed on the weapon that created them, based on some real-life superstitions), some bagged murder evidence that a corp wants incinerated (and is evidently such routine waste they've started outsourcing it), and a scary-looking but harmless biological construct, Obviously there should be something related to either toxic magic or HMMVV, but I don't want it to be too predictable; if they know they're on a hazardous waste train and a sludge spirit or a bunch of half-dead ghouls crawl out of a locker, they'll have seen it coming from miles away. I've said "hazardous", not toxic, so the waste could include magically hazardous stuff, rogue machinery, or anything else that presents some danger in disposal.