Here's an exciting first look at a WDI ride vehicle concept image--taken this June and which recently appeared on the forums.
Ride vehicle research frame from the film.
Full-scale foam mockup.
Note the individual lapbars in the photo above. Keeps little ones locked in tight. Looks like development on the attraction is definitely moving forward. For more details and discussion on the Mine Train, check out this forum thread. Special thanks to Kurt Raymond for the heads-up on this topic.