Crews began hauling in equipment this week for the Birdwood viaduct, and other workers had already started surveying, welding and digging.
The overpass is just west of the Union Pacific Railroad’s Bailey Yard. It will link U.S. Highway 30 to Front Road and offer another entrance and exit to North Platte.
Officials say the project has been discussed for about 30 years.
Union Pacific will pay up to $4.3 million of the cost and Lincoln County will pay a maximum of about $500,000. The state will cover the remaining costs.