How It Works
Power it with a redstone signal and it will activate TNT minecarts and... BOOM! Like powering normal TNT with redstone torch, button, Activated lever, pressure plate, or detector rails.
To craft an Activator Rail, place six iron ingots on each column on the side. Next, place two sticks: one on top and bottom of the middle column. In the middle of the Crafting Table, place a redstone torch.