Residents from five Palo Alto neighborhoods, Menlo Park and Atherton, defined their visions for the California high-speed-rail project at a workshop Saturday.

The two-day workshop, sponsored by the Peninsula Cities Consortium, brought together residents, city and Caltrain officials, architects, and experts in transportation, geology, tunneling, historic resources, finance and public art to discuss the visionary futures for the rail corridor.

The consensus was for undergrounded tracks with parks, community gardens, a bicycle boulevard, green spaces, shops and streets to connect neighborhoods now divided by the at-grade and elevated tracks.

The residents' plans were critiqued by experts Sunday. Their findings will be presented at an upcoming public meeting at the Sheraton Palo Alto Hotel, 625 El Camino Real, Palo Alto.

Most groups said tunneling the trains seemed the best alternatve -- but they recognized the complexity and cost. The groups considered boring deep beneath creeks and avoiding damage to El Palo Alto, the city's iconic redwood.

They looked at changes in elevation for tracks wending through the maze of subterranean obstacles. And they looked at ways to fund the project.

South Palo Alto's vision -- "Rethinking South Palo Alto" -- put all of the trains underground in the area from San Antonio Road to East Charleston Road. A bike and pedestrian path would be added over the top with a landscape buffer between the path and Alma Street, group members said.

Existing adjacent land uses could be extended to the train right-of-way, linking parks, retail and housing to the transit line and the bike-pedestrian corridor.

"The idea is to create spaces where people want to be," said Maryanne Welton, a project manager and the group's table captain. The open space created by under-grounding the trains could also provide space for more soccer fields, a dilemma long under discussion in the city.

Streets now hampered by the train tracks, such as Ventura Avenue, could be connected all the way through, knitting the two sides of Alma Street, the group said.

The second group, representing California Avenue, envisioned "California Connections." They looked at ways to further incorporate California Avenue's retail center into the transit hub.

"We looked at all elevation scenarios, not just to default to the tunnel," Gary Laymon, the group's leader and a landscape architect, said.

Putting the tracks in a U-trench with periodic crossings could save money, but a tunnel provides opportunities to do something different on the surface, he said.

A continuous bike path and linear park on top could extend all the way from California Avenue to University Avenue, with sculptures, an outdoor café and a small performance arena to enhance California Avenue's concept as the "Avenue of the Arts."

Dense housing and a parking structure could also be incorporated along the corridor.

The group also considered "neighborhood connectivity" a primary goal -- bringing one side of the tracks together with the other and promoting access from Old Palo Alto. The group sketched in safety remedies, such as adding stoplights at Seale Avenue and a drop-off for shuttle users.

Residents from the Palo Alto High School/Southgate/Evergreen Park neighborhoods between Embarcadero Road and south of Churchill Avenue considered "a modified trench with some cantilevered portions."

The partially covered trench would recover some of the lost real estate while providing air vents to the underground. Safe houses for emergency medical supplies and community buildings could be added on the reclaimed land, group members said.

A bike path would lead to the Paly track area and housing for teachers could be built along the recovered land. The group also considered ways to keep Caltrain running during construction, by stacking two tracks above one another.

Downtown Palo Alto's vision is for "Reunification -- reclaiming our land," group members said.

The area has "two very attractive regional commercial centers, but they are not connected," residents said. Stanford Shopping Center and Stanford University would connect to downtown by bringing University Avenue back up to grade rather than under the train track, connecting across Alma, El Camino and onto Palm Drive.

The east and west sides of El Camino Real would be reconnected by creating bike and pedestrian routes, they said. A north-south bikeway would link the area to California Avenue and Menlo Park.

Undergrounding the trains would provide reclaimed land to create an attractive boulevard of shops, an arts or cultural center, and cafes to link the two retail areas. The existing sports field off El Camino Real would remain.

University Avenue's Caltrain station would be a high-speed-rail station and "an anchor for the whole area," residents said, with commuter parking, and bus, taxi and shuttle connections.

Envisioning a "Green Connection," the Menlo Park-Palo Alto border area group recommended undergrounding the trains below San Francisquito Creek. A new green belt would incorporate the creek and playing fields, to be paid for through a variety of existing federal and state funds.

The U.S. Fish and Wildlife Service has funds for creek restoration, while the Federal Highways Administration has funds for safe crossings through its safety program and the National Park Service has funding through its Rivers and Trails program, the group leader said.

A connection to link to Alma and Quarry Road would also link to Stanford and the shopping center, they said.

Some groups suggested the project could be funded by a one-percent sales tax hike, as was done in Berkeley when Bay Area Rapid Transit (BART) was built. Others suggested a voter-approved 30-year property-tax fee could cover costs.

Menlo Park and Atherton residents also considered undergrounding the trains, with some proposals to bend Alma closer to downtown Menlo Park and reconfigure El Camino Real. Alluvial soil from the tunnel could be used for South Bay levee restoration, they said.

A series of videos from the meeting will be linked on the Peninsula Cities Consortium website in November at www.peninsularail.com.