Activator Rails, also known as Detonator Rails, are used for activating Hoppers, Command Blocks, and TNT Minecarts. They can be powered with a Redstone signal, at which point they will activate any carts passing over them.
Command Block Minecarts
|Mobs||Horse • Pig|
|Minecarts||Minecart • Minecart with Furnace • 16px Minecart with Chest • 16px Minecart with Hopper • 16px Minecart with TNT • Minecart with Command Block • Boat|
|Rails||Rail • Powered Rail • Detector Rail • Activator Rail|
|Miscellaneous||Carrot on a Stick • Saddle|