Tunnels on the SP Coast Line
September 21, 2023
When traveling between Los Angeles and the Bay Area, I've sometimes noticed the tunnel numbers on the side of the train tracks, and wondered just how high they go. This page has an excellent list of all the tunnels, but it's not entirely clear where each one is. So here I've mapped out all the tunnels on the Union Pacific (ex-Southern Pacific) Coast Line.
Notably, there is a jump in the numbering from 11 (at Cuesta, just north of San Luis Obispo) to 26 (at Santa Susana, on the Los Angeles-Ventura county line). Tunnels 12 and 13 no longer exist, and there were never any tunnels numbered 14 thru 25 on the Coast Line. Numbers 26-28 are in a different series of tunnels, counting up from Bakersfield across the Tehachapi Pass. This entire series is also included on the map.
Fig. 1: This map shows locations of tunnels on the Coast Line and Tehachapi Pass.
Table 1 - Coast Line Series
Counting up from San Francisco
| Number | Approximate Location | Comment |
|---|---|---|
| 1 | 37.761°N 122.392°W | |
| 2 | 37.754°N 122.393°W | |
| 3 | 37.732°N 122.396°W | |
| 4 | 37.714°N 122.400°W | |
| 5 | 37.675°N 122.391°W | Bayshore Tunnel; Bypassed 1956 |
| 5 1/2 | 36.321°N 121.181°W | |
| 6 | 35.349°N 120.635°W | Summit Tunnel |
| 7 | 35.339°N 120.635°W | |
| 8 | 35.333°N 120.636°W | |
| 9 | 35.331°N 120.633°W | |
| 10 | 35.322°N 120.632°W | Bypassed |
| 11 | 35.332°N 120.678°W | |
| 12 | 34.532°N 120.525°W | Bypassed 1956 |
| 13 | 34.472°N 120.301°W | Bypassed 1940 |
The Santa Susana Pass tunnels, numbered 24-26, are listed in Table 2. They are in a different series, counting up from Bakersfield rather than San Francisco. Source 1 makes reference to a Tunnel 14 on the original Coast Line between Saugus and San Fernando. No further details are provied. I cannot find any possible tunnel, historical or current, fitting this description. I suspect the tunnel being referred to is in fact Tunnel 25, listed in Table 2.
Table 2 - Counting up from Bakersfield
This series of tunnels starts in Bakersfield and crosses the Tehachapi Pass, eventually reaching Los Angeles. This series also includes the three Santa Susana Pass tunnels on the Coast Line (numbered 24-26), and the Searles Tunnel (numbered 29) on a spur line to Ridgecrest.
| Number | Approximate Location | Comment |
|---|---|---|
| 1/2 | 35.296°N 118.669°W | Bypassed 1983 |
| 1 | 35.289°N 118.643°W | |
| 2 | 35.286°N 118.656°W | |
| 3 | 35.269°N 118.623°W | |
| 4 | 35.267°N 118.623°W | Bypassed |
| 5 | 35.268°N 118.616°W | |
| 6 | 35.271°N 118.618°W | Bypassed |
| 7 | 35.262°N 118.594°W | |
| 8 | 35.255°N 118.594°W | |
| 9 | 35.200°N 118.538°W | Tehachapi Loop |
| 10 | 35.198°N 118.531°W | |
| 11 | Bypassed | |
| 12 | Bypassed 1922 | |
| 13 | Bypassed 1922 | |
| 14 | 35.180°N 118.490°W | |
| 14 | 35.177°N 118.485°W | |
| 16 | 35.177°N 118.483°W | |
| 17 | 35.175°N 118.482°W | |
| 18 | 34.428°N 118.350°W | |
| 19 | 34.431°N 118.356°W | |
| 20 | 34.430°N 118.389°W | Bypassed |
| 21 | 34.425°N 118.394°W | Bypassed |
| 22 | 34.419°N 118.418°W | Bypassed |
| 23 | 34.411°N 118.474°W | Bypassed |
| 24 | 34.421°N 118.540°W | Bypassed |
| 25 | 34.346°N 118.514°W | San Fernando Tunnel |
| 26 | 34.264°N 118.632°W | Santa Susana Tunnel |
| 27 | 34.264°N 118.616°W | |
| 28 | 34.272°N 118.605°W | |
| 29 | 35.467°N 117.623°W | Searles Tunnel |
I couldn't figure out exactly where tunnels 11 thru 13 are located on a map, other than that they were between numbers 10 and 14. Source 2 says Tunnel 11 was "right at the present west switch of Marcel," and Tunnels 12 and 13 were just north of Tunnel 14.
Sources
- www.modelingthesp.com/Structures/Tunnels.html
- www.trainorders.com/discussion/read.php?1,1700036
- Various historical USGS maps with railroad tunnels marked