The Port of Long Beach Harbor Commissioners approved an $870 million budget for an on-dock rail facility that plans to largely shift cargo movement from trucks to trains.

The project, dubbed the Pier B On-Dock Rail Support Facility, makes up the bulk of the port’s overall $1 billion rail improvement project.

The 171-acre site is currently used as a storage and staging area for trains and is an important center in the port’s rail network, said Lee Peterson, spokesman for the port.

The first phase of the on-dock rail expansion will entail planning and design, followed by bids for engineering and other construction projects, Lee said. Actual construction is estimated to be three years out from now, he added.

The expanded rail tracks are expected to be completed in 2024, with additional tracks added by 2030, followed by project completion in 2032.

Manufacturing, retail and trade reporter Shwanika Narayan can be reached at [email protected] or 323-556-8351. Follow her on Twitter @shwanika.