forceload chunks only for a specific time

Is it possible to forceload a chunk for let's say only 30 seconds?
I know I could set a schedule to unload after a time, but I have minecarts that are traveling and loading chunks (3x3 around them), so I would somehow have to store all the chunks to unload them after their individual timer.
Currently I have the minecarts unloading chunks in a 5x5 circle around them, but this messes up the chunk loading of other minecarts if they are near each other.
Another Idea I have is that I could check if any other minecart is near and then only unload when there is no minecart near. But this could lead to some chunks staying loaded forever.