Minecarts go down spirals slowly

When pushing a minecart down this spiral, it goes down slowly compared to when the Minecart Improvements experiment is disabled.

Steps to reproduce:

1. Create/open a world with the Minecart Improvements experiment enabled

2. Build a spiral:

   [media]

3. Place down a minecart at the top and push it down the spiral

Observed result:
The minecart goes down the spiral slowly.

Expected result:
The minecart goes down the spiral quickly, like when the Minecart Improvements experiment is disabled.