Minecart with TNT bug/glitch

When TNT minecarts explode, the tracks and blocks the tracks were sitting on.

What I expected to happen was...:
I expected the tracks to explode

What actually happened was...:
The tracks did not explode, nor the blocks they where sitting on.

Steps to Reproduce:
1. Make a rail loop with an activated activator rail.
2. Send a TNT minecart on the track
3. Wait for TNT to explode