The fastest trains in the U.S. are about to get faster.

Beginning this month, the government will allow railroads to operate passenger trains capable of traveling up to 220 mph.

There’s just one catch: No U.S. track can handle that much speed.

When the Federal Railroad Administration rule—which introduces new safety and high-speed standards—goes into effect on Jan. 22, the maximum speed of Amtrak’s Acela Express, currently the nation’s fastest train, will bump up to 160 mph from 150 mph. That might shave a few minutes off some trips—the Acela can travel at its fastest in only two spots along the Northeast Corridor—but the promise of greater speed lies ahead.

With infrastructure improvements, the top speed in the Northeast Corridor could increase to 186 mph. California is in the midst of a high-speed project to connect eight of its 10 largest cities. And Texas developers are acquiring land for high-speed rail between Dallas and Houston.