Minecart rework (speed and rendering / chunk loading)

The recent (experimental) firework speed decrease is related to render distances and travel speeds. 

Minecarts, even on powered rails, have a pretty low speed and a significantly higher cost in terms of materials and initial time required. To compensate, a minecart should be faster than an elytra, or at least significantly faster than it moves currently However, simply raising the speed when there are already problems at these high speeds isn't a solution. The minecart speed can still be increased, but minecart rails can guide directed chunk loading in a small radius around them. This will not cover the render distance, but, since rails would be a form of long distance and frequent transportation, the full area does not need to be rendered. At high speeds on low end devices, this could even be masked with a blur effect