WASHINGTON — Amtrak will use a $19 million grant from the Federal Railroad Administration to convert an idle track into a lower-level passenger platform.

Known as Track 22, it currently serves as a storage track for equipment, with no access for customers.

The construction project will involve installing new track, rebuilding the platform and restoring historic columns at Union Station’s lower level. A new elevator, escalator and stairs will also be installed to give passengers access to the lower level.

The new platform, which will be used by both Amtrak and Virginia Railway Express passengers, will open in 2022.

Amtrak has undertaken an ongoing $2.4 billion investment into Union Station and its trains. New, faster Acela trains come in 2022. Union Station is also rebooting its commuter rail concourse, nearly doubling its current capacity.

Union Station is Amtrak’s second-busiest station, behind New York’s Penn Station.