I guess it all depends on what kind of technology/mechanics they use for the swinging of the cars. Will they be gravity based and just swing freely back and forth? Or will it be a tightly-controlled swing built into the track?
The "4D coaster" X2 out at Six Flags Magic Mountain uses a special track that rotates the seats around their support axis. At its heart, this track/vehicle design is essentially an Omnimover, and in fact the coaster is built by Arrow, the company that helped Disney build the first Omnimover systems.
A secondary set of wheels follows a rail along the track, and changing the position of the second rail relative to the main support rail causes the seats to rotate.
If the Mine Train track was built in a similar fashion, they could easily design the train to tilt the cars left or right exactly the same amount at exactly the same point in the track, every time. There's no varying in the swing of the cars dependent on the weight of the riders or the speed of the cars around the corners.
And because the tilting would be 100% mechanical, there are no hydraulics to breakdown, no computer systems that don't get the proper signals and do the wrong thing at the wrong time (like the time our vehicle in Pooh started bouncing in the Tigger scene and continued to bounce until the end of the ride...)
-Rob
