If a minecart is at the bottom of a downward rail track it won't begin to move automatically like it usually does when there's a solid block at one end of a powered rail. Furthermore you cannot get it to move when you get inside it and use your movement keys

Reproduction Steps

• Build this setup
  
• Place a minecart on the sloped rail
• Get into the minecart
• Face the redstone torch and press W

Observed Results

• The minecart doesn't automatically drive out of the dip after being placed
• When you get into the minecart you can't get it to move by pressing movement keys

Expected Results

• The minecart would move on its own since there's a solid block at the end of the track (already established behaviour which happens on even rails)
  
• You would be able to make the minecart move by pressing movement keys while riding it