Using Reactor 2. I have the drag turned off as well as friction, but the coaster is still losing energy. In simple tests. (A simple U shaped hill) the coaster will go back and forth losing very little energy. But the problems start to arise at greater speeds and sharper turns in direction. If you make a more V shaped track, but still a smooth trasnition from down to up, the coster will fly down and then go back up, but not as far as it should. Even with no drag or friction. From what I have tested, the energy is lost by tring to keep the wheel constraints at the proper location. In the “U” shaped test, the G-forces are low as the car is pushed back up and the wheel constraint can easily redirect the travel to follow the track. But in the “V” shaped test, the G-forces are greater then what the wheel constraint can handel (stragth and Tau = 100%) If you study the animation closely you can see that the wheel is pushed up compared to the coster cars. The wheel is push through the axle. Meaning the parent space (of the car) and the child space (of the wheel) are NOT in the same location. So energy is redirected to realign the wheel constraint so parent and child space are in the same location. Thus reducing the kenetic energy the coaster has and stopping short of its initial height.
Its kinda like putting 2 tons on a 1 ton trailer, your going to break the the axle, so to fix it you can add another axle. reducing the weight on each one. Thats the same thing you need to do with Reactor…Less wieght or more wheels to support it.