If there can be a positive outcome in a tragedy like the Interstate 35W bridge collapse, it came Thursday when the Minnesota Department of Transportation announced that it is fast-tracking the replacement of two aging bridges used by thousands of drivers in St. Cloud and Hastings.

The 35W collapse led to scrutiny of bridges across the nation. In the flurry of inspections that followed, serious questions arose about St. Cloud's DeSoto Bridge and the Hwy. 61 span in Hastings. Like the 35W bridge, both are considered "fracture-critical," meaning one component's failure jeopardizes the entire structure.

MnDOT's announcement came after months of assurances that the current bridges were safe for continued use. Still, its decision to move quickly -- construction will begin this year on the new St. Cloud bridge and in 2010 on the Hwy. 61 span in Hastings -- makes sense. The crumpled 35W wreckage still sitting near the Mississippi River is tragic proof of the need to err on the side of caution when it comes to bridges. And thanks largely to legislators who voted for the new gas tax, MnDOT has the money to act. Better to rebuild now than spend millions to shore up moribund spans already slated for replacement within the next decade.

MnDOT's bold and timely action may well have averted future tragedy. At the same time, the St. Cloud bridge replacement in particular raises anew the troubling question: Could the 35W collapse have been prevented?

Federal investigators probing the 35W collapse are focusing on the possible failure of underdesigned steel gusset plates -- the braces that hold steel beams together. Two weeks ago, MnDOT closed the St. Cloud bridge after finding quarter-inch bends in four gusset plates.

The National Transportation Safety Board's investigation of the 35W collapse recently brought to light photos suggesting that bent gusset plates on the doomed bridge were detected in June 2003. They were taken by the consulting engineering firm URS Inc.

A MnDOT spokeswoman has said it's not clear if these plates were bent; physical measurements would be needed to determine this. Yet the agency's assistant St. Cloud district engineer told Star Tribune reporter Tony Kennedy that the 35W bridge gussets looked more deformed than the St. Cloud bridge's.

Who had possession of these photos? Who reviewed them and decided against measuring the plates or taking other action? Why did inspection reports of the 35W bridge contain no mention of gusset plate bowing?

So far, answers have not been forthcoming. Nor will there be a public hearing in which to raise them because the NTSB decided not to hold such a hearing.

In 1996, an Ohio bridge on busy Interstate 90 closed after bowed gusset plates caused dangerous sagging. While it's reassuring that lessons learned from the 35W bridge could avert other disasters, it's haunting to think that the photos and the Ohio bridge may have been early warnings of danger ahead in Minneapolis.