User blog comment:SomeoneYouUsedToKnow/SYUTK's V4E10 - Guroyuri - Impressions/Recap/@comment-3965075-20170124035703

Actually, it makes a lot of sense for the train to have some type of force field. I remember in the CCTS episode of WoR that before the System was brought up, Grimm were often a major obstacle of physical delivery of goods and information. Maybe one type of Dust fuels the train itself, while another type projects a sort of "force field" to provide additional armor to the vehicle.