While Palo Alto's decisions about how to reconfigure its rail crossings are still months if not years in the future, the City Council is nonetheless queuing up plans to build underpasses for pedestrians and bicyclists first so that they'll be able to cross under the tracks even as work progresses on the ambitious roadway-redesign projects.

The ultimate goal of Palo Alto's grade separation effort is clear — rebuild the rail crossings so that tracks and roads would no longer intersect — but the exact locations, configurations and scopes the new road and bike amenities are still being hashed out, subject to community input, council review and approval from Caltrain, which owns the tracks.

This week, two options, one for Churchill Avenue and one for Meadow Drive and Charleston Road, appear to be pulling ahead. In both cases, the designs call for leaving the railroad tracks in their existing locations and building new underpasses for cars, bicycles and pedestrians under the tracks. Both are also relatively recent options that were pitched by local residents and that are now being further refined by staff and consultants. And the council is looking in both cases at starting with the bike/pedestrian underpasses.

"We've come to recognize there's a good chance we'd want to go with a bike and pedestrian crossing here, and perhaps down south, preceding the vehicular crossing," committee Chair Pat Burt said during a Tuesday, May 23, discussion of the Churchill Avenue grade crossing. "So that it's in place so that bikes and pedestrians continue to have full access when we do vehicular construction."

The new bike underpasses will also be explored as part of the city's update to its Bike and Pedestrian Master Plan, which is set to kick off later this year and take about 18 months to complete, according to Chief Transportation Official Philip Kamhi.

Over the past several years, the city has entertained as many as 30 design concepts for its rail crossings. But finally, the city's vision for what the new roadways and bikeways may look like is starting to become less abstract and more concrete.

One idea that picked up momentum at the council Rail Committee's meeting on Tuesday is construction of a bike underpass at Seale Avenue as part of a "partial underpass" that the city is envisioning for Churchill. The council last year chose the Churchill underpass, which submerges Churchill west of the tracks and allows cars to turn onto Alma Street, over two other previously considered options: a soaring viaduct and the complete closure of Churchill to cars west of the tracks (the closure remains a backup option, should the underpass prove to be infeasible).

To retain access for bicyclists and pedestrians looking to cross the tracks during the construction period, the city is now looking at building a bike tunnel that would stretch along Seale and end at Peers Park. The east ramp for the bike tunnel would begin on Seale about 215 feet east of Alma. The underpass would then terminate in a location next to the Peers Park's tennis courts. The city still needs to figure out ways to connect the ramp to Park Boulevard, the main bicycle route in the area south of Paly.

The idea for the Seale bike path picked up steam this week when the Rail Committee unanimously agreed that this alternative is superior to another previously considered option: a bike underpass at Kellogg Avenue. The Kellogg option, which staff has been analyzing for well over a year, is now on the verge of being scrapped after staff and consultants determined that it would be far more complex to construct because of its location next to the Palo Alto High football field. The western portion of Kellogg ramp would effectively cut into the space currently occupied by bleachers on the field.

After hearing presentations on the two options, all three committee members agreed that Seale is by far the better choice, notwithstanding unanswered questions about how the path would connect to existing roads west of the tracks.

"There's a lot more flexibility with this than with the Kellogg (underpass) but also with that flexibility there's not the path right there that you'd connect to," Kamhi said. "You'd really want to get over to Park."

How south Palo Alto plan is shaping up

A different debate is occurring in south Palo Alto, where the council is plotting new bike and pedestrian paths near the Meadow and Charleston crossings, which are being evaluated in tandem. The plan that city is currently considering envisions a single two-way bike underpass on the south side of Meadow and another one on the north side of Charleston.

The city had also considered another alternative — building bikeways on both sides of Meadow and Charleston — though that option now looks unlikely to move forward. A new study by Hexagon Transportation Consultants, the city's consultant for grade separation, concluded that this alternative "would not be able to adequately accommodate existing or future vehicle traffic."

Gary Black of Hexagon told the committee Tuesday that from a traffic-flow standpoint, building two bike paths on either side of Meadow and Charleston would create massive delays. That's because the bike improvements would require the city to prohibit various vehicular turns at the intersections of the two streets with Alma. These include the southbound off-ramp and northbound on-ramps on Alma at East Meadow and the southbound on-ramp on Alma at Charleston.

These changes, according to Hexagon's model, would push more traffic on to Charleston because cars on Meadow that would otherwise turn on Alma would now take Charleston to make the turn.

Furthermore, traffic going east on Charleston would no longer be able to turn left onto Alma to turn north. Rather, cars would need to cross Alma, make a U-turn at a roundabout and then make a right turn at the Alma and Charleston.

"The resulting increase in traffic on the connecting ramps on Charleston would just completely overwhelm the capacity of this design," Black said.

The underpasses at Charleston and Meadow constitute one of three alternatives that the city is still considering for grade separation in south Palo Alto. Other options that remain in the mix are a trench and a "hybrid" design that includes raising the tracks and lowering roads.

The trench alternative, while popular among many residents, is by far the most expensive option on the table, with an estimated price tag of about $950 million. It would also require the city to obtain permission from various regulatory agencies to divert Adobe and Barron creeks and from Caltrain to build the trench at 2% grade (Caltrain's preferred maximum grade is 1%).

The hybrid option is estimated to cost about $230 million, though some of its design elements — namely elevation of trains — has made it less palatable to residents in neighborhoods near the tracks.

The Rail Committee, which consists of Burt and council members Ed Lauing and Vicki Veenker, discussed the refined plans for the underpasses near Churchill, Meadow and Charleston and unanimously agreed to forward them to Caltrain for review. The committee also voted to favor the Seale bike and pedestrian crossing over the Kellogg one and supported adding a 4-foot-tall landscaped buffer zone between the sidewalk and Alma near Churchill. And given Hexagon's recent findings, members opted not to change the single-path configurations of the bike and pedestrian underpasses at the southernmost rail crossings.

Will construction be at 'a date uncertain'?

Even as Palo Alto continues to chisel away at the details in each of the city's grade-separation alternatives, it remains unclear when construction on the colossal project would actually kick off, how much it would cost and how long it would take.

Funding remains a big question mark. While the passage of Measure B in 2020 is expected to bring about $350 million to Palo Alto for construction, this is unlikely to cover grade separations at all four of the city's rail crossing.

Furthermore, the council has yet to kick off the planning process for its northernmost crossing at Palo Alto Avenue, choosing to lump it in with a broader downtown study that is not expected to start at least for another year.

That said, the city is hoping that its newly developed concepts will bring it closer to its ultimate goal of separating tracks from all city streets. Doing so is essential to accommodating more frequent Caltrain service that would result from the agency's current electrification project, and potentially, California high-speed rail service.

To further this effort, the council unanimously approved on May 22 a service agreement with Caltrain that would enable the transit agency to review Palo Alto's plans as they are being developed and ensure that they comply with Caltrain's regulations and design standards.

The agreement, which requires Palo Alto to pay $106,677 to Caltrain, is the first of what is expected to be a series of deals between the city and the agency as they work to refine plans for grade separation. The new service agreement would terminate at the end of 2024, after which time the city and the agency would likely enter into a new contract for collaboration on design reviews, budget development and requests for proposals for advancing the project, according to the agreement.

"It is assumed by the parties that the City of Palo Alto and Caltrain will collaboratively develop future scopes of work to reach consensus on the work needed to advance the project to the next phase," the service agreement states.