South Linden Avenue and Scott Street
Grade Separation (LSGS)
1 Project Status Update by Caltrain
January 22, 2025
Project Partners and Roles
2 Lead Implementing Agency
Major Funding
Partner Project Sponsors
Forecast Gate Down Times at Peak Hours
(Long Range Service Vision – Adopted Moderate Growth Scenario) 3 Trains will be passing through the grade crossing every few minutes.
Information from City of San Bruno City Council Meeting Presentation on November 29, 2019.
Background: Project Location/Key Features
South San Francisco Station
Colma Creek
N
San Bruno Station
City Border
Scott St
1,850 feet
to San Francisco to San Jose
South Linden Ave
Southline
Development
I-380
UPRR/
Granite Rock
PSR Alternative 1 – Requirements
5 ❑ Lowering roadway 7 ft, elevate railroad 15
ft. and build railroad bridge
❑ Elevate Caltrain tracks for one mile with
retaining walls
❑ Electrified shoofly (detour) tracks
❑ Significant property and partial building
acquisition/modifications
❑ Relocation of UPRR/Granite Rock tracks
plus fiber optic and utilities
❑ Shoofly and railroad construction within
safety envelope of operating, electrified
trains
Alternative 1: Hybrid
Rail Partially Elevated and Roadway Partially Lowered
South Linden Avenue
Rail Elevated 15 ft
Roadway Lowered 7 ft
PSR Alternative 1 – Design Footprint
5600 ft
Rail Elevated – 15 ft
Road Lowered –7 ft
6 Optimized Alternative (OA)
7 Airgas
S. Linden Ave
Westside Materials
Central Concrete
The evaluation revealed a refinement of the
PSR alternative. A “jacked box” or Optimized
Alternative that has the following characteristics
and advantages:
❑ Retains key features of S. Linden Grade
Separation
❑ Lower risk (due to less ROW, no track
impacts to UPRR/Granite Rock, fewer
environmental impacts, faster
construction)
❑ Fewer railroad operational impacts
❑ Lower cost
Box Jacking
❑ Push or "jack" a precast concrete box beneath existing tracks ❑ Keeps existing railroad tracks
❑ Eliminates shoofly and elevated tracks
PSR Alternative 1 – Design Footprint
5600 ft
Rail Elevated – 15 ft
Road Lowered –7 ft
9 Optimized Alternative – Design Footprint
Rail Elevated – 2 ft
Road Lowered – 20 ft
10 11
Design Alternative Comparison
Project Element
PSR
Alternative 1
Optimized
Alternative
Construction Schedule 84 months 36 months
Construction Cost $450 $320
Property Owners Impact Extensive Moderate
1,2,3,4
1 Dollars shown are in millions.
2 Based upon escalation of 5% to midpoint of construction 3 Assumes all funding available when required
4 Estimate not adjusted for risk
Slide does not show total project cost
Similar Project – Jefferson Avenue in
Redwood City
12 ❑ Road lowered approx. 24 ft
❑ Track kept at existing elevation
❑ Fully accessible for
peds/bikes/autos
❑ Retaining walls allow for
building construction and
landscaping
Video Rendering of
South Linden Ave - OA
13 ❑ Road would be lowered by 22 ft
❑ Track would be raised less than 2 ft
❑ Fully accessible for
peds/bikes/autos
❑ Retaining walls allow for building
construction and landscaping
Summary
With new analysis of the design, constructability, and risks, Caltrain endorses the Optimized Alternative as a more effective and realistic option to advance forward with design.
By contrast, the PSR Alternative is least practical alternative due to:
➢ 7-year construction duration
➢ the large impacts (ROW, the environment, the footprint, traffic) ➢ the higher cost, higher risk, and fundability
➢ the impacts of safety clearances
➢ the construction inefficiencies (constrained site access, electrified operating railroad environment)
14 Next Steps
• On-going engagement with property/businsess owners
• Winter through Spring 2025
• San Bruno City Council – Action on staff recommendation • January 28th, 2025
• South San Francisco City Council
• February 12th, 2025
• Environmental Phase
• Preliminary engineering (15%-35%)
• Project team planning for next phase of the design work 15