The project is mainly concerned at this stage with the “big pieces” of the revamped station, officials said, although creating an “iconic space” at the site is the ultimate intent.

The Union Station revamp components potentially include an integrated high-speed rail system; co-location of bus operations; a new and expanded passenger concourse; and opportunities to expand conventional and light rail in the future. Development could occur underground, atop the existing Union Station site, or even expand beyond current site boundaries into surrounding areas, depending on what form the final plan takes.

A key component of the Wednesday presentation is a plan to integrate high-speed rail into the existing station. Potential solutions include running high-speed rail tracks above the existing rail yard, creating underground access, or potentially expanding the footprint of Union Station to create an all-encompassing “transportation district.”

Since the creation of high-speed rail for California is in a very preliminary stage and faces many potential obstacles, the designers allowed during Wednesday's presentation that a plan would be developed that does not rely on any one component. Instead, the various schemes “would need to work on their own,” said Deborah Gerod, a partner at Gruen Associates, the co-designer of the various site plans. Grimshaw Architects is the other designer for the draft proposals.

The Union Station Master Plan team unveiled its concepts after an initial seven months of data collection, analysis and outreach to various stakeholders. The designers indicated that the current passenger concourse was built for an era of lower ridership, and they want to integrate an improved passenger concourse so that those coming to the station are funneled to a central point.

Still to come: many meetings with the community, tweaks to the plan based on feedback, additional debate, and final confirmation and decisions by the Metro Board of Directors on what concepts will move forward. The anticipated conclusion may come as early as spring of next year, although there is an “official” summer deadline.

Union Station was originally designed by John and Donald Parkinson and built in 1939. It was intended at the time to serve as a transcontinental terminus station for the Union Pacific, Santa Fe and Southern Pacific Railway companies. The historic terminal is 161,000 square feet and was placed on the National Register of Historic Places in 1980.

The station was restored by its prior owner in 1992 and the next year added the Metro Red/Purple line. Bus and shuttle service opened in 1995, followed by the Metro Gold line in 2003. Metrolink's commuter rail offers stops for six of its seven lines at Union Station, while Amtrak offers long distance train and bus service.

As reported earlier by GlobeSt.com, public involvement in the Union Station planning began in June, 2012, with a community kickoff meeting.