The Los Angeles Metropolitan Transportation Authority has released a movie detailing its proposal to extend the city's historic Union Station building with a ring-shaped, glazed passenger concourse.

Los Angeles Metropolitan Transportation Authority (Metro) created the video to visualise the design as part of a major overhaul of the station, which was built in 1939 in the city's downtown area.

Metro's project, which is called Link Union Station (Link US), aims to help Union Station function more efficiently and provide a better traveller experience.

Key features of the scheme include the addition of high-speed rail, and the transformation of the station's stub-end – or dead-end – tracks to run-through tracks. This will allow trains to leave the station without turning around, and passengers to travel straight through to major destinations in Southern California.

Among other proposed upgrades are a new passenger concourse to the east of the station, including shops, food stalls and waiting areas. This is shown in the video as an elevated, ring-shaped structure that loops around above the train yard and central passenger platforms. Tall, glass walls would offer panoramic view of the platforms on one side and to the city on the other.

An angular structure is shown to jut out from the circular concourse above the landscape western plaza. This building would be punctured by a set of lifts, shown housed in glass volumes, for accessibility.

Other access is provided by a series of staircases connecting the different levels between the concourse and the plaza.

One platform would hosts ticketing booths for trains, with escalators leading down to renovated train lines. The Amtrak Club lounge would be placed across the square to face this, while Gold Line access would be set at the mezzanine level above.

Metro purchased Union Square Station in 2011 and developed the masterplan with a team led by British firm Grimshaw Architects and local firm Gruen Associates.

The raised design, which is estimated to cost between $1.7 billion and $2.1 billion (approximately £1.3 billion and £1.7 billion), provides one alternative for the scheme.

Metro is also planning an alternative ground-level design, which is estimated to be more expensive, costing $2.2 billion to $2.6 billion (£1.7 billion to £2.0 billion), and will be explored in a second upcoming video.

Union Square Station – one of the major transportation hubs in Southern California – was constructed in 1939. The building was designed by John Parkinson and Donald B Parkinson, along with a group of assistant architects.

The station features a combination of styles, including art deco, and mission revival – a colonial revival style that became popular at the turn of the 19th century and was often used for California rail depots. Other features refer to streamline modern, a later interpretation of art deco.

Renderings are courtesy of MBI Media/Youtube.