Construction has begun on a BNSF railroad bridge over the Mississippi River in Burlington, Iowa. The work began ahead of schedule to build a new lift-span bridge that will more than double the navigation channel for barges up to 307 feet. The Coast Guard has long wanted the bridge repaired because barges frequently hit the span, which has happened 92 times between 1992 to 2001. Congress allocated $55 million for the bridge work. Officials still haven't decided the full extent of work on the 118-year-old bridge beyond replacing the lift span. About 30 trains a day cross the bridge and the span opens about 300 times a month for river traffic.