Thanks to a recent addition to the Java Edition game rules in Snapshot 24w33a, commands can now be used to increase the maximum speed of minecarts.

The One Player Seeping game command in Java Edition (Image via Mojang) The necessary One Player Sleep command in Minecraft is effectively the same across both editions of the game.

You can see chunk borders in Minecraft: Java Edition using wireframes, and in Bedrock by using coordinates.