OIL ABOARD: U.S. and Canadian drillers are producing oil faster than new pipelines can be built. As a result, trains have become an unexpected yet vital way to move this bounty of energy. This year, more trains carrying crude will chug across North America than ever before — nearly 1,400 carloads a day. In 2009, there were just 31 carloads a day.

SAFETY QUESTIONED: Earlier this month, 50 people were killed in Lac-Megantic, Quebec, near the Maine border, when a runaway train carrying 72 carloads of crude derailed and sparked an explosion.

TRAINS WILL KEEP CHUGGING: Experts say tank cars that carry crude could be made stronger, but rail is an increasingly safe mode of transportation. Also, oil isn't as hazardous as many other substances shipped by train. Pipelines can be hard to permit and build, and refiners like the flexibility and speed that rail offers — along with access to domestic crude, which is often cheaper than imported oil.