Amtrak has issued a solicitation for letters of interest in a construction manager-at-risk contract (CMAR) for the $1-billion first major contract of a planned three contracts that make up a nearly $5-billion passenger rail tunnel megaproject in Baltimore.

The plan calls for replacing the 149-year-old Baltimore & Potomac Tunnel with two new high-capacity ones, named for Frederick Douglass, the prominent abolitionist and native of Maryland.