The Caltrain Tunnels: Bayshore to 4th & King
This post is on Caltrain’s legacy tunnels in San Francisco, how they relate to UPRR operations as well as CHSRA’s plans for reaching downtown SF, plus the issue of the stabling/light maintenance yard at the north end of the starter line. My apologies to readers in the Central Valley and Southern California for the third Caltrain-related post in succession. In my defense, the core objective of the post is to look for ways to reduce total project cost and it just so happens that this short section represents valuable low hanging fruit.
Here is a map showing the relevant features in this section of the preferred HSR route, to be discussed below.
View Caltrain Tunnels in a larger map
Description of the Status Quo
PCJPB owns and Caltrain operates four short tunnels between the Bayshore station and its 4th & King terminus. They are numbered 1 through 4 southbound and were seismically reinforced with shotcrete in the 1990s, so they’re in a state of good repair. Tunnel #2 actually features two bores that once supported a total of four tracks. Only the eastern bore is active, I do not know if the western bore was also reinforced.
The active tunnels all feature two tracks and are suitable for electrification via overhead catenaries, see cross-section of tunnel #4 as an example. Caltrain’s 22nd Street station is located directly under the I-280 freeway in-between tunnels #1 and #2, with the tracks running in-between the supports. It currently supports around 1000 average weekday boardings, out of 36,000 total.
The following video shows the view from a northbound train running through this section of the Caltrain corridor. Note the two remaining grade crossings at 16th and Berry streets north of tunnel #1 and the forest of freeway support columns to either side of the tracks.
UPRR still owns and operates a spur for rail freight into and out of the Port of SF, an agency that earned a total of $2.1 million in fees between 2001 and 2008. The spur branches off the northbound track just north of tunnel #3. They’ve asked for a gauntlet track through tunnels #3 and #4 to enable, for the first time, extra-tall AAR plate H autorack cars for the purpose of transshipping imported automobiles stacked two high. For electrical safety, such cars could only pass through these tunnels if the future overhead catenary system were temporarily switched off. In addition, the OCS would have to be strung at a higher level all the way to Santa Clara. Considering total remaining freight volume in the SF peninsula, Clem Tillier has recommended that PCJPB banish US-style heavy freight by designating the entire SF peninsula a so-called “short line” with an axle load limit of 22.5 metric tonnes (European standard for light/medium freight), a gradient limit well above 1% and the present AAR plate F vertical clearance.
A separate turnoff into the polluted former Navy shipyard at Hunters Point via Caroll St, located in-between tunnels #3 and #4, appears to have been abandoned for lack of customers (though I’m not 100% certain of that). For a primer on this troubled neighborhood, please refer to the history of Bayview-Hunters Point.
Separately, the old Southern Pacific yard just west of the Bayshore station is the subject of the vast 4500 home Baylands development project, which is in an advanced planning stage. The entire area on both sides of the tracks is landfill and was contaminated by diesel spills, heavy metals and household waste, respectively. The cost of remediating the entire area to the level required for residential use is estimated at $100-$200 million and would have be funded by the developer.
Sections 0 and 1 of the exhibits for the preliminary alignment alternatives in the SF peninsula indicate that CHSRA intends to either run at grade or construct a new deep tunnel all the way from Transbay Terminal to Bayshore. The freeway supports in the area mean the new tracks would have to run either just west of the existing ones (under 7th St near 4th & King) or else, directly underneath them.
The program EIS/EIR had called for tracks at grade south of 22nd Street, which would have cut the total distance tunneled in half. An at-grade alignment featuring additional tracks would eliminate 7th St south of Townsend St and, require new road underpasses for 16th and Berry St (referred to as Common St on the exhibits). The option of a road overpass at Berry, which is right next to the Mission Creek outfall, appears not to have been considered. Nor was closing the crossing altogether.
Note that the document’s author(s) failed to include the map for section 2 through Brisbane, duplicating section 3 instead. The full report (p10 PDF) shows CHSRA intends to leverage Caltrain’s existing quad tracks at grade between tunnel #4 and Sierra Point. P33 PDF suggests express HSR trains would run past or through narrow UPRR’s south San Francisco marshalling yard at grade as well, though speeds are limited by the necessarily tight curve at Sierra Point. An aerial option is also under consideration, though p66 PDF suggests that would prevent UPRR access to the south SF yard and the spur east to its customers Granite Rock and Central Concrete.
Confusingly, CHSRA’s Google Map of the HSR route (please zoom in) still shows tracks at grade south of 22nd Street, except for short tunnels adjacent to Caltrain’s existing tunnels #3 and #4, respectively. It also shows a trench section through the Baylands, presumably to permit a change in track order, i.e. where the HSR tracks will end up laterally relative to Caltrain’s. The animation NC3D produced suggests HSR would use the center tracks south of tunnel #4, but the final decision on that has not yet been taken.
P42 PDF echoes scoping comments from the San Francisco sessions that relate to visual and noise mitigation at “the maintenance yard”, presumably meaning the one HSR will use for overnight stabling and light maintenance. However, the document makes no mention of where that yard is to be located.
Not that no-one has ever suggested siting the system’s heavy maintenance facility (HMF) in SF, politically the most likely site for that is the Central Valley.
Analysis of Required Track Count
In the interest of cutting costs, CHSRA should generally seek to absolutely minimize expensive tunnel construction throughout the entire network, including both mountain and urban/suburban sections. There is a business case for the DTX tunnel between 4th & King and the new Transbay Terminal, because a downtown station will generate greater ridership for the starter line. In addition, AB3034 explicitly defines it as the northern end point, essentially regardless of construction cost, throughput capacity or feasible dwell times. The section south of 4th & King is not part of the definition of the DTX tunnel, but both HSR and Caltrain obviously need to reach it.
Between Bayshore and 4th & King, HSR speeds will be below 80mph, slowing down sharply to negotiate three tight curves at 7th/Townsend, 2nd/Townsend and 2nd/Transbay Terminal. This implies that HSR and Caltrain could potentially share the two (2) existing tracks and remain at grade until the first of these curves.
Other than obvious rent-seeking on behalf of the construction industry, there appear to be three distinct reasons planners are currently still considering quad tracking north of Bayshore:
(a) Regulatory contraints. At this point, CHSRA is not yet ready to submit a request for a “rule of special applicability” with FRA. New rulemaking is required to operate trains at speeds in excess of 150mph and many other aspects of HSR operations. In particular, CHSRA has so far assumed that getting the green light from FRA would only be possible if non-compliant HSR trains ran on dedicated tracks throughout its entire network with the exception of the DTX tunnel. The original plan to serve Anaheim via mixed traffic operations in a newly grade separated dual track section south of Fullerton was eliminated in favor of quad tracking, last not least to avoid falling foul of FRA.
However, the fact that Caltrain got a waiver subject to conditions that could just as easily apply to HSR in standard-speed sections suggests that FRA is actually more receptive to mixed traffic than it has been in decades.
(b) UPRR operations. Presently, UPRR uses a short afternoon window in Caltrain’s operations to move freight cars between the Port of SF and the south SF marshalling yard. As mentioned before, the existing turnout to the freight spur is only connected to the northbound main track, such that southbound marshalling trains have to run through tunnel #3 in reverse direction before they can cut over to the southbound main track.
Both HSR and Caltrain plans assume increased operations throughout the day, making the afternoon window impractical. The Caltrain waiver already includes a provision to restrict freight traffic to the wee hours of the night, ostensibly on safety but really on operational grounds. This may not be as onerous as it sounds if transshipping imported cars into plate H autoracks becomes the Port of SF’s primary activity, since those could only pass through tunnels #3 and #4 at night, when the OCS can be switched off.
Passenger cars actually constitute comparatively light freight, so even the axle loads would be modest and much lighter locomotives could be used to haul the goods to Santa Clara.
(c) Caltrain + HSR operations. The commuter railway, which just declared a fiscal emergency after cuts in its operating subsidies, is proceeding on the assumption that large capital investments in electrification and a modern EMU fleet will make it profitable enough to not just maintain but grow its ridership while sharply reducing its appetite for operating subsidies, at least on a per-passenger basis. Its plans call for not 5 but 8-10 trains per hour each way during peak periods by 2025.
The full grade separations that CHSRA is offering in return for part of the ROW would avoid one negative side effect of such growth in rail traffic: any remaining grade crossings would be closed much more frequently during rush hour, potentially prompting motorists to try and swerve around the gates with statistically predictable results.
For its part, CHSRA is cheerfully predicting sufficient ridership to support 7-8 trains per hour each way between SF and the other three end points on a fully built-out statewide network: Anaheim, San Diego and Sacramento. If/since the design of the Transbay Terminal station and throat cannot support that volume of traffic, the idea is to use 4th & King for overflow capacity. AB3034 sets a hard limit of 24 stations total for the statewide network, so using not one but two of those for SF would require a station elsewhere to be cut. Sylmar in the northern San Fernando valley has been mentioned, ostensibly due to problems in securing a suitable ROW through or under land owned by the Disney Corp. land in Santa Clarita.
However, if HSR really becomes popular enough to support 7-8 trains per hour into SF, each potentially a full-length consist of bi-level cars offering 1000-1500 seats depending on layout, it might make sense to terminate some in San Jose or else at Millbrae/SFO. Indeed, by that time there may well be calls to find a ROW and funding for a spur up the East Bay to Oakland Coliseum.
If you optimistically add up Caltrain’s and CHSRA’s service forecasts and assume that they have overlapping peak periods, then and only then would sharing the existing two tracks between Bayshore and 4th & King imply a total of 15-20 trains per hour each way. Modern signaling permits as many as 30 (cp. Mattstetten to Rothrist in Switzerland), provided they travel at very compatible speeds and there are zero stops on the main line. An therein lies the rub, as Caltrain’s 22nd St station is surrounded by freeway supports. The sloped embankment just west of those could perhaps be modified to permit the construction of additional tracks at the same level, but such tracks could not merge back into the main line anywhere south of 4th & King. A deep underpass at 16th and closing the Berry St crossing would be possible, but eliminating 7th St south of Townsend would present a severe traffic restriction for businesses west of it.
The station is the 11th or 12th busiest in the Caltrain corridorv and, ideally located for ridership growth the new UCSF campus in Mission Bay. Nevertheless, given the very high cost of quad tracking, it might make sense to take a hard-nosed approach and provide only bare-bones commute-period Caltrain service there. Think in terms of just 2 trains per hour, albeit with extra-long trainsets to deliver a meaningful level of capacity. Braking, dwelling and accelerating back up again will eliminate HSR slots on the timetable during rush hour, but that may be a price worth paying: Caltrain serves more northbound than southbound commuters in the early morning, when there aren’t any northbound HSR trains full of passengers to worry about yet. That means more Caltrains could stop at 22nd St northbound at that time without constraining HSR service. Southbound morning commuters would have the option of either timing their arrival at the station to coincide with the rare train that does stop at 22nd St or else, walking or cycling up to 4th & King/Townsend via Townsend St.
The upshot is that none of the reasons for quad tracking in this section really holds water.
Analysis of HSR Yard Options
On a separate note, CHSRA’s apparent lack of foresight in securing overnight stabling capacity – never mind light maintenance – for its fleet near the SF terminal is remarkable. The issue of yards, which this blog has touched on in May of 2009, is simply not addressed at all in the preliminary alignment alternatives documents for the SF-SJ section.
The old Bayshore yard would be easily large enough and fairly close to SF. Yard operations there would not require the same level of a priori remediation needed for a residential development that would anyhow have to deal with a very busy rail line. The applicable target for trace contaminants would presumably be set by OSHA. Nevertheless, once again hosting a large rail yard is not at all what the city of Brisbane has in mind for Baylands, even if an elevated Geneva Ave were extended across the yard.
Perhaps CHSRA is assuming that some of Caltrain’s platforms at 4th & King could be demolished, turning part of that into a stabling yard for a subset of late evening trains, since Caltrain will be running to Transbay Terminal whenever it can. Unfortunately, this logic does not hold true if, as previously assumed, Caltrain itself needs to stable a larger fleet to support expanded commuter operations.
UPRR’s marshaling yard in south SF would be too small and will anyhow not be available as long as there are freight rail operations in the northern peninsula. There may not even be an opportunity to quad track the main line at that location, given that UPRR owns the tracks to either side outright.
Constructing a brand-new yard in the Bayview/Hunters Point district would likely be opposed on the basis of impacts to industrial businesses if not environmental justice, even though it would bring a useful number of jobs to this depressed area. Besides, the main line runs well above the grade level of land to either side there.
It might just be possible to construct a run-through yard in San Bruno, immediately north of the Millbrae/SFO station. This would imply terminating a subset of late evening trains at that station and asking passengers headed for SF to transfer to either Caltrain or BART. The southern turnoffs toward 101 would be located in-between where the BART ramps to SFO run. The northern turnoffs would thread the needle between the BART portal and 1st Ave, which would double as the access road. Technically, the area is designated “Marina Vista Park” but it’s only partially landscaped and anyhow sandwiched between two major transportation arteries. The view is of SFO, not the Bay. Note that Caltrain’s San Bruno station is due to be moved north to W San Bruno Ave, though the design may need to be modified to ease the curve radius for HSR operations.
An alternative concept would be for some late-night HSR trains into SF to turn around and make a final revenue run of the day south to SJ Diridon. In the early morning, those would execute revenue runs back up to SF before resuming normal statewide service. Of course, that would reduce the number of northbound Caltrains that could stop at 22nd St.
Conclusions and Suggestions
- Both CHSRA and Caltrain should assume that reducing the cost of the corridor improvements while maintaining as much of the functionality as possible is paramount. CHSRA cannot secure prop 1A bond appropriations until and unless it has matching non-state funds. To that end, PCJPB could pro forma cancel some of Caltrain’s big-ticket projects (electrification, signaling R&D) and reprogram those dollars to related aspects of the HSR effort, which the regional service would then leverage. That implies letting CHSRA make the vendor decisions, even if that means continuing diesel operations for longer than originally planned. There are ways to plug the operating shortfall until then, e.g. reprogramming the balance of Caltrain’s $41 million share of prop 1A to CHSRA in return for cash on hand associated with guarantees related to using the ROW for HSR even if Caltrain has to shutter operations.
- Without HSR, there will be no full grade separation of the entire corridor anytime soon. Any attempt to actually implement the Caltrain 2025 plan to double rail traffic volume without those would surely be challenged in the requisite CEQA proceedings due to the impact on cross traffic at all remaining grade crossings. If upheld, Caltrain would be limited to running much longer trains, which wouldn’t be close to full during mid-day runs. Reconfiguring every consist twice a day every weekday is possible but perhaps not sufficient to sustain the business case for electrification and PTC implementation, absent full grade separation.
- However, even if Caltrain’s own projects are merged more completely with CHSRA’s, with the latter organization actually taking the lead, it will still be necessary to drive down total project cost even further. The funding simply is not there yet and intelligent cost cutting increases the probability of closing the gap. Among the lowest hanging fruit in the entire corridor is to simply exploit the already existing dual track rail infrastructure between Bayshore and 4th & King more intensively, even though that will mean reduced Caltrain service frequency at the 22nd St. station and also constrain UPRR service to the Port of SF to nighttime operations. In other words: no new mainline tracks at all in this stretch.
- Optionally, construct gauntlet tracks for AAR plate H cars through tunnels #3 and #4, with implications for OCS height all the way to Santa Clara. Ideally, get UPRR to accept an axle load limit of 22.5 metric tonnes and a 2% limit for gradient transitions in the corridor as a quid pro quo. Sweeten the deal with electrification out the port of SF plus a free electric locomotive if need be. The cost of accommodating heavy rail or else, of abandonment proceedings, could be much higher and lead to more CEQA challenges against the corridor upgrade project.
- Construct a deep road underpass at 16th St, with a short bridge connecting 7th St to Mississippi St.
- Close the Berry St. grade crossing and pave over a dirt section under I-280 to connect it to Channel St. on the Mission Bay side.
- Begin a 3.5% effective curved descent into the DTX tunnel immediately north of the hydrological tunneling hazard posed by Mission Creek. There are already four tracks side-by-side, use the ones in the center for this purpose and reconnect the outer ones to the platforms at 4th & King as far west as possible. The radius of the entire curve may need to be increased at the expense of some utility buildings and tracks right at the corner of 7th and Towsend. Even then, flange lubrication will be needed to avoid excessive squeal noise in the neighborhood. Also, Caltrain might want to consider Talgo 22 bi-level rolling stock for its self-steering wheelsets that avoid flange contact by design. However, that choice would have consequences for vendor lock, platform height, acceleration, cost etc.
- Give the search for a viable overnight stabling strategy for HSR high priority in the project-level planning process as it might have implications for service patterns in the early morning and late evening, with consequences for ridership predictions. There are no easy options but without adequate parking, you cannot fire up the service in the morning. If Bayshore is not available or too contaminated, San Bruno and/or the San Jose gambit should be explored. If at all possible, stabling should always be implemented at the lowest possible cost, i.e. at grade and, with minimal deadhead run distances.
- Do not deprive another deserving city elsewhere in the state of an HSR station just to turn 4th & King into a second one for SF. If need be, ask the state legislature to modify or re-interpret the 24 station limit of AB3034.