 The north portal of the tunnel in 2023 | |
| Overview | |
|---|---|
| Line | Corte Madera-Sausalito Line |
| Location | Marin County, California |
| Coordinates |
|
| Status | Unsafe, sealed |
| System | Northwestern Pacific Railroad |
| Crosses | Camino Alto |
| Start | Corte Madera, California (north) |
| End | Mill Valley, California (south) |
| Operation | |
| Opened | April 1884 |
| Closed | November 1971 |
| Traffic | Railway |
| Character | Passenger and freight |
| Technical | |
| Length | 2,173 feet (662 m) |
| No. of tracks | 1 single-track |
| Track gauge | Narrow-gauge |
| Tunnel clearance | 20 feet (6.1 m) |
| Width | 16 feet (4.9 m) |
The Alto tunnel is a disused railway tunnel in Marin County, California that connects the towns of Mill Valley and Corte Madera. It was built in 1884 by the Northwestern Pacific Railroad as part of the Corte Madera-Sausalito line. The tunnel is narrow-gauge and single tracked, with a length of 2,173 feet (662 m) and a cross section 16 feet (4.9 m) wide by 20 feet (6.1 m) high.[1][2][3]
- ^ "Alto Tunnel Investigation and Cost Estimates Update – 2017". dokumen.tips. McMillen Jacobs Associates. December 2017. Retrieved 2024-03-06.
- ^ "Alto Tunnel - Mill Valley, California". wikimapia.org. Retrieved 2024-03-07.
- ^ Palmer, John (February 2018). "AN ALTO TUNNEL PRIMER" (PDF). Scott Valley Homeowners Association. Retrieved 2024-03-06.