South Linden
Avenue and
Scott Street
Grade
Separation
(LSGS)
February 12, 2025
1 Stakeholders and Roles
2 Lead Implementing Agency
Primary Funding
Agency Project Sponsors
Project Location/Key Features
South San Francisco Station
Colma Creek
N
San Bruno Station
City Limit SSF and SB
Scott St
1,850 feet
to San Francisco to San Jose
South Linden Ave
Southline
Development
I-380
UPRR/
Granite Rock
3 PSR Alternative 1 Requirements
4 ❑ Lowering Roadway 7 ft, elevate railroad
15 ft. and build railroad bridge.
❑ Elevating Caltrain tracks for one mile
with retaining walls
❑ Electrified shoofly (detour) tracks with
❑ Significant property and partial buildings
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
5 Optimized Alternative (OA)
6 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 total project cost
Optimized Alternative – Design Footprint
Rail Elevated – 2 ft
Road Lowered – 20 ft
7 Design Alternative Comparison
8 Project Aspect PSR Alternative 1 Optimized Alternative Construction Schedule 84 months 36 months
Estimated Total Project Cost $450M ~28% less than PSR1
Risk High Low
Environmental Impacts High Low
Road Closures / Traffic Impacts Long duration Moderate duration Operational Impacts (RRs) Extensive Minimal
Project Footprint Impacts Extensive Moderate
1 Dollars shown are in millions and based upon 2024 estimates. 2 Based upon escalation of 5% to midpoint of construction in year 2032 1,2
Caltrain endorses the Optimized Alternative as a more effective and realistic option to advance forward with design.
Pre
Recommended Action / Next Steps
9 Staff Recommendation is to proceed with the Optimized Alternative Next Steps:
• Continue with the Preliminary Engineering (up to 35%) • Continue development and minor refinements of the OA design and agreements
• Continue outreach and gather feedback from Caltrain, city managers, and other stakeholders
• Start the Environmental Review Process
• Project Sponsors to Seek Funding for Remaining Phases of Design Questions / Action
10