picture of map for better zooming: https://imgur.com/a/Hx67xQN
I made a concept map for a hypothetical southern extension of SMART beyond the current Larkspur terminus, continuing through southern Marin and ending in downtown Sausalito at Dunphy Park. Obviously this is fantasy planning, but I tried to keep it tied to real geography and realistic constraints instead of just drawing random lines.
>Red line: at-grade route
Yellow line: tunnel route
Blue squares: station
The route would start with a relocated Larkspur station placed much closer to the ferry terminal. The current station is nearby, but its a walk and not integrated in a way that feels seamless. I have the SMART rising onto an elevated structure over the road and ferry parking lot, with a station directly serving the terminal, before continuing south on a new bridge across Corte Madera Creek.
From there it would continue along the old rail right-of-way to a station near The Village at Corte Madera, then continue south toward Mill Valley by taking over Koch Rd. and turning it into rail. The houses in this neighborhood are able to use a different road for egress, but this segment could potentially be a short tunnel if there is too much opposition from neighbors.
The hardest part of the alignment is the Alto area, where 101, roads, and development all squeeze together. I originally wanted to continue alongside 101 on the East side and across a new bridge parallel to the Richardson Bay Bridge, but it does not seem feasible. Therefore I went with a short 1 mile tunnel under Mill Valley with one underground station at Alto. Expensive, but cleaner than forcing rail onto frontage roads or building awkward elevated structures. And this tunnel allows us to get onto the old rail right-of-way south of Corte Madera.
SMART would re-emerge and continue along the former rail corridor, currently a bike path. I am picturing double-tracked SMART plus a rebuilt bike path alongside it, with a stop near Tamalpais High School / Altamont.
I originally had the line ending near Waldo for simplicity, but it felt like stopping short. If you are going to spend all this money, I think it makes more sense to push another mile into downtown Sausalito. A Southern terminus at Dunphy Park station gives you an actual destination with waterfront access, tourism, restaurants, local trips, and a station people would genuinely use.
I have the route staying close to the northeastern edge of Bridgeway, which would require removing some smaller commercial businesses and parking lots. Nothing too major, but this is probably the most complex segment, and honestly it might not be feasible. Crossing gates would be used at the at-grade crossings through this section. I wanted to extend all the way to the Sausalito Ferry, but it was too difficult to get beyond Dunphy Park at grade, and a tunnel that close to the water sounds impossible.
There are obvious downsides to this plan overall. The tunnel would be very costly, especially with a station. The final segment into Sausalito would be politically (extremely) difficult, and street crossings across the tracks would remain. Marin is NIMBY central, so I have serious doubts about the overall political feasibility. The biggest issue is that this expansion would be massively more expensive than other SMART extensions:
| Extension | Length | Cost | Cost per Mile |
|---|---|---|---|
| San Rafael → Larkspur | 2.1 miles | $55mm | $26mm / mile |
| Santa Rosa → Windsor | 3 miles | $70mm | $23mm / mile |
| Windsor → Healdsburg (in progress) | 5.5 miles | $269mm | $49mm / mile |
| Larkspur → Sausalito (proposed) | 7.5 miles | $2 - 3B | $267mm – $400mm / mile |
I also included a screenshot from Open Railway Map showing the current SMART route (shown in orange) and the abandoned former rail ROW (dashed brown) that I’m using in this proposal. Source: https://www.openrailwaymap.org/
Main idea was to imagine SMART not stopping short at Larkspur, but continuing into southern Marin in a way that actually serves real places like Corte Madera, Mill Valley, and Sausalito. Southern Marin used to have direct rail access before passenger service faded out in the 1940s and much of the old right-of-way was later lost or repurposed. This was basically an attempt to imagine what a modern version of that connection could look like today.
Would love feedback, especially from Marin folks!
>Edit: If anyone is interested, I also built a Light Rail Speed Map comparing train speeds across 17 transit systems. If this post interests you, check it out here: https://www.reddit.com/r/transit/comments/1rw8fd4/i_built_an_interactive_speed_map_of_17_light_rail/