A runaway train of tanker cars carrying shale oil barreled into Lac-Megantic, Quebec on July 6. It exploded, spilled more than 1.5 million gallons of heavy crude and killed 47 people in the small town.

Lac-Megantic is a small town. It's sobering to consider what might happen if such an incident occurs where tracks pass through heavily populated urban areas.

So, the derailment Monday morning in Philadelphia of a train carrying the same type of oil involved in the Lac-Megantic catastrophe should be taken by state and federal regulators to be a dire warning. Six tanker cars of the CSX train derailed on the Arsenal Bridge, above the Schuylkill River and the busy Schuylkill Expressway, and within a few blocks of three hospitals and the University of Pennsylvania campus. No one was injured and none of the tank cars' 90,000 gallons of oil spilled.

It was one incident in a nationwide epidemic of oil train accidents. According to the Pipeline and Hazardous Materials Safety Administration, more than 1.15 million gallons of crude spilled from rail cars in the United States in 2013. That doesn't count a number of incidents in Canada. And it is stunning considering that about 800,000 gallons of crude oil spilled in train incidents from 1975 through 2012.

The increase reflects increased domestic oil production, which is a good thing for the economy and national security. But it's apparent from the railroads' performance that they are not prepared to handle that increase.

State and federal regulators should mandate the use of double-hulled tank cars, routes that evade major population centers, low speeds, track upgrades on routes used by oil trains and all other technological and operating improvements that can enhance safety.