Shrugs and finger-pointing aren't enough. The region's 65,000 daily round-trippers into Grand Central Terminal on Metro-North's New Haven line deserve solid answers about its disruption. So do 10,000 Amtrak Acela riders between Boston and Penn Station.

Here's what we know:

A 138,000-volt Con Edison cable that feeds electricity to Metro-North's overhead power lines failed near Mount Vernon last week when oil -- which acts as an insulator -- somehow got into the line. A second power cable over the tracks had been taken out of service for an upgrade.

So the juice went out on eight miles of track in Westchester County, and the outage spread chaos up and down the line as trains -- and their passengers -- jerked to a halt.

Here's what we need to know:

How did oil get into a live feeder line? Anyone with a good answer isn't saying publicly. And was it smart to upgrade the power feeder without getting a backup ready? Again, it's the sound of silence.

This isn't just about personal inconvenience.

Connecticut's economic health depends on the health of the rail system, Bridgeport Mayor William Finch reminded reporters last week. Manhattan's employers -- especially in midtown around Grand Central and Penn -- could make similar arguments. The construction of a temporary power substation in Harrison now lets Metro-North run at about 50 percent of capacity on the line. (Amtrak hopes to resume most of its Boston-New York service Tuesday.)

Sens. Charles Schumer (D-N.Y.) and Richard Blumenthal (D-Conn.) are asking New York State's Public Service Commission and the federal Office of Electricity Delivery and Energy Reliability to find answers to the power-line mess. We're eager to see results.

This isn't Metro-North's only crisis lately. In May, 70 were injured when a Metro-North train derailed near Bridgeport. In July, a trash-filled CSX freight jumped the tracks on the Hudson line. Just a run of bad luck? Or does Metro-North have deeper problems? It's time for the MTA's inspector general to take a look.