The rail line is the only land link to the subarctic town of 900 people, and was washed out by heavy flooding in the spring of 2017.
Since then, goods and people have had to be flown in and prices for groceries and fuel have skyrocketed.
A consortium of northern communities reached a deal recently to take over the rail line and port from Denver-based Omnitrax.
The federal funding consists of $74 million to help with the ownership transfer and necessary repairs.
Another $43 million will subsidize operations of the rail line and port for the next 10 years.