Minecarts accelerate on regular rails as if they were powered in some situations

This affects the minecart experiments snapshot
You can notice it after increasing the minecart movement speed (I set it to 1000)

A rail track built with alternating power and regular rails will provide more momentum than a shorter track with the same number of power rails.
This doesn't make sense since it's the power rails providing the acceleration.

Steps to reproduce

• Build a 15 block long powered rail track
• Build a track with 15 power rails but one regular rail alternating between them

Observed Results

• The minecart on the shorter track is much slower
  

Expected results

• Both minecarts would be the same speed due to having equal amount of propulsion
• OR the minecart on the longer track would be slower due to losing speed on the parts where it wasn't being accelerated