After numerous detours, Palo Alto is preparing to advance its most complex, expensive and potentially divisive public infrastructure project in decades: a reconfiguration of the city's rail corridor so that the tracks no longer intersect with streets.

The effort, which the City Council is preparing to discuss next week, hit a major milestone earlier this month when a specially appointed citizens committee released a 171-page report evaluating possible design alternatives for the rail crossings at Churchill Avenue, East Meadow Drive and Charleston Road. After exploring dozens of options over several years, the Expanded Community Advisory Committee recommended closing Churchill to traffic and eliminating the possibility of tunnels in south Palo Alto.

The committee's recommendations for the rail corridor, which the council would need to approve, would cost roughly $60 million to implement. In closing the Churchill vehicle crossing, a tunnel would be constructed for bicyclists and pedestrians underneath the tracks and Alma Street. Concurrently, the city would proceed with a wide range of traffic improvements at Embarcadero Road and Oregon Expressway — modifications designed to keep traffic at these busy arteries from getting worse once the Churchill intersection is reconfigured.

In voting 6-3 to support the closure of Churchill, the panel picked that option over two other alternatives: a viaduct for trains and what's known as a "partial underpass" that would send eastbound cars under the tracks and to a new T-intersection at Alma.

At the same time, the panel hit a stalemate when it came to picking the best design options for the two south Palo Alto crossings — East Meadow and Charleston — ultimately concluding that it needs more information before it can make a decision. None of the four options on the table for the East Meadow and Charleston crossings — a trench, a viaduct, an underpass and a "hybrid" design in which the tracks are raised and the road is lowered — were able to secure support from a majority of the committee members.

The panel did, however, agree to eliminate from consideration a south Palo Alto train tunnel, a popular option that city leaders and the panel concluded is infeasible for numerous reasons, not the least of which is a price tag exceeding $1 billion.

The new report comes at a time when Palo Alto and other cities along the Peninsula are taking a fresh look at their rail crossings and making plans for change to accommodate an expected growth in trains as Caltrain moves ahead with electrifying its fleet. Measure B, which Santa Clara County voters approved in 2016, allocates about $700 million to Palo Alto, Mountain View and Sunnyvale for grade separations, though the Santa Clara Valley Transportation Authority has yet to determine how to distribute these funds.

Concurrently, both the California High Speed Rail Authority and Caltrain are advancing their own plans for, respectively, introducing and expanding train service on the rail corridor. Caltrain is also preparing to launch a grade separation study that considers all 41 of its at-grade rail crossings between San Francisco and San Jose.

Adding to the complexity is Caltrain's rail corridor use policy, which states that grade separation alternatives must not preclude the agency from installing a four-track segment somewhere between north Palo Alto and Mountain View sometime in the future.

Given the various limitations and the high costs of all the other engineering alternatives, XCAP concluded that the closure of Churchill is the most viable option, notwithstanding concerns from neighbors about the impact on traffic. Compared to the underpass and the viaduct, the closure would be the "least disruptive alternative," the report concluded, and would have only minor noise impacts during the construction period, which is expected to last about two years.

Costs were a major factor in XCAP's decision. Closing Churchill and adding a pedestrian/bike tunnel along with various traffic improvements on Embarcadero and Oregon would cost between $50 million and $65 million, according to the report. A partial underpass would cost between $160 million and $200 million, while the viaduct comes with a price tag of between $300 million and $400 million.

The panel is also recommending a list of mitigations to improve traffic flow around Embarcadero and Alma Street. These include reconstructing the Alma overpass at Embarcadero and adding a right-turn lane from eastbound Embarcadero to Kingsley Avenue, as well as a left-turn lane from southbound Alma to Kingsley. New traffic signals would be installed at the Alma overpass at Embarcadero and at Kinglsey.

The menu of traffic improvements proposed by the city's traffic consultant, Aecom, also includes traffic signals at the Alma Street ramps on Oregon Expressway, as well as a northbound right-turn lane from Oregon to El Camino Real.

A key element in the plan is the Churchill tunnel, which would allow Palo Alto High students and other pedestrians and bicyclists to safely cross the tracks and Alma Street without stopping. The panel preferred a longer tunnel, which crosses under Alma Street, over a separate alternative, which called for a shorter tunnel that would end before Alma and require pedestrians and bicyclists to wait for a green light to cross Alma.

Not everyone, however, is thrilled about the potential of Churchill closing. The proposal to close the street to traffic has polarized the Southgate neighborhood, which lies across Churchill from Palo Alto High School. Some residents have argued that shutting off Churchill to traffic would eliminate a critical access point for their part of the neighborhood. At the same time, some residents of Professorville, which lies north of Embarcadero, have charged that the move would drive more cars to the historically congested Embarcadero.

While some residents, particularly those who live farther from the rail corridor, favored designs that keep Churchill open, the panel concluded that the viaduct would pose construction challenges (including the need for temporary "shoo-fly" tracks) and create an eyesore. The panel also decided that additional expenditure to study the underpass alternative is not justified and that it is "unlikely to be improved with additional design iteration."

Despite the recommendation, some members of XCAP remained concerned about the traffic impacts of the Churchill closure. The panel voted 6-3 to adopt the recommendation, with the dissenting members all supporting conducting further analysis and gathering more information before committing to this option. Nadia Naik, chair of XCAP, said she and two of her colleagues — Keith Reckdahl and Phil Burton — wanted further traffic analysis and additional evaluation of the partial underpass. They also wanted the city to consider retrofitting the existing Embarcadero grade separation, which dates back to 1936 and which could be redesigned to facilitate smoother traffic flow and more turning movement.

Naik noted, however, that the changes proposed in this alternative to ease traffic — including traffic lights at the Alma ramps at Oregon Expressway and new turn lanes on Oregon and Embarcadero — would be worth pursuing even if Churchill were to remain open.

"One thing we really agree on is that a lot of mitigations Aecom proposed — if they did them tomorrow, they would significantly improve the city," Naik said in a recent interview.

Larry Klein, a former Palo Alto mayor and vice chair of XCAP, said members of the panel disagreed from time to time about the degree of certainty that is needed before a council selects a preferred alternative. Six members, including himself, concluded that they had all the information they needed about the three Churchill alternatives to recommend closure.

"You can't proceed down the line on a full basis with every possible alternative, unless you have unlimited funds and unlimited time, which neither one was the case here," Klein said.

The Charleston Dilemma

The feeling of uncertainty was even more pronounced in considering reconfigurations for south Palo Alto, where the committee confronted a menu of high-priced options: hybrid design (estimated price tag: $190 million to $230 million), an underpass for cars and bikes and pedestrians ($340 million to $420 million), a viaduct ($400 million to $500 million) and a trench ($800 million to $950 million). It also considered — and eliminated — the idea of a south Palo Alto tunnel, which would cost between $1.2 billion and $1.8 billion, according to Aecom estimates.

"Because of this high cost, significant construction time and other drawbacks, XCAP unanimously decided to remove the tunnel alternatives from further deliberation," the report states.

When evaluating the remaining alternatives, the committee confronted a major design challenge: Each of these options was envisioned as a two-track alternative and, as such, may not meet Caltrain's requirements. That, Naik said, led the panel to decide unanimously that it needed more information before a majority could support any alternative.

"So instead, as a group, we decided to go through all the pros and cons to be able to really teach the council, in a way, what we learned about what really matters in the various alternatives, to at least help them be able to then continue to narrow it down," Naik said.

The trench alternative, for all of its popularity, poses particular challenges. To construct the trench for the train tracks, the city would need to build pump stations and divert Adobe and Barron creeks; gain Caltrain's permission for a 2% grade on the rail corridor (the agency's standard is 1% grade); and build shoo-fly tracks for trains to use during the construction period, which would last between five and six years. Supporters of this alternative observed that the trench would remove trains entirely from view and improve neighborhood aesthetics without requiring any acquisition of private property. Opponents noted that this is the most expensive alternative and raised concerns about how the structure would affect creeks and groundwater.

The viaduct also proved polarizing, with proponents noting that it could be built most quickly and that the land under the raised structure could be used for other purposes as a public benefit. Opponents pointed at the high visual impact of the elevated structure in a residential neighborhood — a criticism that they also extended to the "hybrid" alternative.

The underpass, which was only recently added to the menu, is the only option that would fully separate bikes and pedestrians from Alma Street, and its cost is expected to be lower than for the tunnel, trench and viaduct. But the underpass, which also includes a traffic circle on Charleston Road, would require more private properties to be acquired than any other option under consideration — a key factor for a council that has been reluctant to invoke eminent domain for grade separations.

The report recommends that the council selects Churchill closure as its preferred alternative; explore new bike and pedestrian crossings on Alma Street at Seale and Loma Verde avenues; and formalize outreach to the Palo Alto Unified School District, the bike community and other major stakeholders. XCAP is also recommending that the council launch a geotechnical and hydrology analysis, explore further road mitigations and engage with Menlo Park and Caltrain to explore a grade separation at Palo Alto Avenue, the city's northernmost rail crossing and one that it hopes to analyze as part of a future downtown study.

Partnerships, clear communication and strong advocacy are particularly critical given uncertainty over funding. Klein noted that unless the city comes up with the huge sums of money to pay for grade separations, the council's role in the process will be that of an advocate rather than a decision-maker.

Naik concurred.

"What's become more urgent is the need to be able to think about both the needs of Palo Alto and reach out to our neighboring cities and regionally to be able to figure out how to tackle problems together," Naik said. "It's not just Palo Alto. All 41 remaining grade separations would need to be completed for Caltrain to reach its goal. … If we band together, we have the best chance for attracting dollars and getting things done."

View the full report:

The report can also be viewed here.