What I find most interesting is the "Ghost Trains".
Chapter 3:
The robberies were all similar, save for the one at the playhouse. A train was stopped because of a distraction on the tracks—early on, a fallen tree. Later, a ghostly phantom railcar that appeared from the mists, traveling directly at the train. The engineers stopped in a panic, but the phantom ahead vanished.
I noted several things about this passage:
1. the first time, the Vanishers did not have phantom train technology. They seem to have gained it sometime after the first robbery, or maybe because of the first robbery.
2. The train comes out of the mists.
Theories: Phantom Trains are not, as far as we know, part of any magic system on this world. I have come up with several theories on what could cause them, ranging from plausible to extremely implausible.
1. The engineers are working for the Vanishers, and lying about what they see. (Very plausible, although I don't think it's likely)
2. The train is shaped from mist. (Possible, but it would seem that that would require Sazed's intervention)
3. Bendalloy mistings create and take apart the phantom train. (already discussed)
4. The train is some sort of Atium shadow (very implausible, I have no idea how this would work)
5. A very large kandra is mimicking a train. (more of a joke than a theory)