From: "Chris Graves" email@example.com
Subject: Central Pacific Railroad Tunnels, c. 1870
Tunnels on TRACK #1:
Tunnel #0 – Driven in 1873 as part of the line change to eliminate Deep Gulch trestle. This tunnel is East of Clipper Gap, abandoned in 1942. It is horse-shoe shaped, lined with granite from the Rocklin quarries. Following its abandonment, it was used for a while as a growing garden for mushrooms, however that venture was not successful financially. West of the tunnel face 100 yards was found a rail chair in 2002, as well as several original construction spikes.
Tunnel #1 – Driven in 1866 as a single track at Grizzly Hill, widened for the second track during double tracking work of 1913. 514.70 feet long, concrete lined.
Tunnel #2 – Driven in 1866 about one mile East of the settlement of Emigrant Gap, to further locate it was about 200 yards East of the trestle over Emigrant Gap, now (2005) filled in. This tunnel was driven through the West end of Smart Ridge. It was daylighted for the second track alignment, Emigrant Gap to Andover, in 1923-1924. Original length was 271 feet.
An interesting feature can be found about one mile East of this daylighted tunnel: A stone wall was built in 1866 to stop avalanches from taking out the grade, the stone wall is still in place (2005).
Tunnel #3 – East of Cisco at Mile Post 180.7, on a 9 degree curve, unlined. Originally 280 feet long, in 1984 it measured 269 feet. Please note: As you stand on the West Portal of this tunnel, trains are coming at you, DOWN THE HILL. It is impossible to see or hear a train until it exits the tunnel; a dangerous place to be, in the extreme. [Tunnel 3 was one of those worked partly by nitroglycerine. In consequence of using nitroglycerine about 20% of the men working on the tunnel struck and were not replaced. Thus only 2 shifts worked tunnel 3 but by using nitroglycerine they kept up with the work in the headings. Gillis goes on to say 'It will be seen (in Appendix E) that, after allowing for the smaller force employed, about twice as much work was done per man, with nitro-glycerine as with powder.']
Tunnel #4 – East of Cisco, at Mile Post 181, it is curved on a 8 degree curve. Originally 92 feet in length, in 1984 it measured 85 feet. Both Tunnel #3 and Tunnel #4 were driven thru solid ['Trap Rock' called 'ironstone' by the builders, described by Gillis in his 1870's reports as 'black limestone' and 'dark blue quartzite.']
Tunnel #5 – Located East of Cisco at Mile Post 185, at a spot called Crocker's Spur, built on an 8 degree curve, unlined, originally 128 feet in length, daylighted about 1895.
Tunnel #6 – Known also as Summit Tunnel. Unlined, originally 1,659 in length, in 1984 it measured 1,653.4 feet. All original tunnel were enlarged in the 1960's by having their ceiling raised some 2 feet, except Tunnel #6, which had it's floor lowered some 2 feet.
Tunnel #7 – Located at Mile Post 194.1, length was 100 feet, it was was daylighted, and then a concrete roof was constructed, replacing the removed stone roof. It was unlined, now out of service.
Tunnel #8 – Located at Black Point, at Mile Post 194.3, original length was 375 feet, it measured 361 feet in 1984. Now out of service.
Tunnel #9 – Located at Mile Post 194.9, original length was 216 feet, in 1984 it measured 205 feet. Now out of service.
Tunnel #10 – Located at Cement Ridge, at Mile Post 195.1, original length was 509 feet. Now out of service.
Tunnel #11 – At Spur, Mile Post 195.4, original length was 577 feet, now out of service.
Tunnel #12 – At Spur, Mile Post 195.7, original length was 342 feet, in 1984 it measured 328.50 feet. Out of service.
Tunnel #13 – At Lakeridge (Andover), Mile Post 200.1. Original length 870 feet, in 1984 it measured 865.8 feet.
Tunnel #14 – At Alder Creek, Mile Post 222. Length was 200, abandoned in 1913 due to line change of double tracking.
Tunnel #15 – At Quartz Spur, Mile Post 225, original length was 96, daylighted about 1895, abandoned 1913 due to line change of double tracking.
Mile Post noted are on the West Portal, Tunnel #14 and #15 Mile Post as noted in this report are not exact.
Tunnels on TRACK #2:
Tunnel #15 – Do not confuse this with the Tunnel #15 on Track #1. The Tunnel #15 on Track #1 was daylighted in 1895, and then abandoned in 1913 — Tunnel #15 (the Second) is located at Mile Post 114.20 East of Rocklin, alongside what is today (2005) Sierra College Blvd. Built in 1912, its length is 1,904.76 feet, concrete lined.
Tunnel #16 – Located East of Rocklin, at Mile Post 114.7. Length is 777.65 feet, concrete lined. This tunnel runs alongside of what is today (2005) Sierra College Blvd.
Tunnel #17 – Located at Mile Post 117.3. Length is 1,648.16, of which 1,259.16 feet is concrete lined, gunite only covers 189 feet, timber posts between concrete ribs 200 feet. Built in 1912.
Tunnel #18 – Double tracked with Track #1, at Mile Post 120.5, just East of the Village of NewCastle. Length is 1000 feet, concrete lined, built in 1912.
Tunnel #19 – Located at Mile Post 122.7, West of the Nevada Street Station in Auburn, length was 377.37, driven in 1912, daylighted between January 1, 1974 and January 1, 1976. In a book by Stephen Ambrose, printed in 2001, entitled Nothing Like it in the World, Mr. Ambrose mistakenly said this tunnel was still in existence, and took the place of Bloomer Cut. In fact, Bloomer Cut is still on Track #1, and is in use today (2005), while the tunnel is no longer in existence.
Tunnel #20 – Located West of Auburn Station on Nevada Street, and West of the bridge over I-80, at Mile Post 123.1. Length is 1,248.33 feet, of which 112.33 feet is concrete portals, 276 feet gunited with steel bents, the balance is gunited with no steel bents. Built in 1912.
Tunnel #21 – At Mile Post 124.60 on the 1912 line, East of Auburn Station at Nevada Street, length is 1,210.66 feet, of which 531 feet is lined with concrete portals, 428 feet of gunite with steel bents, 43 feet is gunite only, and 208.66 feet with timber posts between concrete ribs.
Tunnel #22 – At Mile Post 131.2, near Clipper Gap, built on the 1912 line. Length is 984.69 feet, of which 116 feet is concrete lined portals, 188 feet is gunite with steel bents, 680.89 feet is gunite only.
Tunnel #23 – At Mile Post 132.7 on the 1912 line, immediately next to the abandoned Tunnel 0, but a few feet lower in elevation. length is 843.66 feet, concrete lined.
Tunnel #24 – At Mile Post 132.9 on the 1912 line. Length is 300.66 feet, concrete lined.
Tunnel #25 – At Mile Post 133.1 on the 1912 line, length is 771.66 feet, concrete lined.
Tunnel #26 – At Mile Post 133.3 on the 1912 line, length is 149.82 feet, concrete lined.
Tunnel #27 – At Mile Post 133.8, on the 1912 line, West of East Applegate. Original length was 855.49 feet, then shortened to 686.91 prior to 1984. Partially daylighted between 1959 and 1968; leaving 351.91 of concrete lined tunnel, 335 feet of timber posts between concrete ribs, and 55 feet of concrete barrel at the East end. The East Portal was left in place.
Tunnel #28 – At Mile Post 134.8 on the 1912 line, it is West of East Applegate. Length is 3,208.86 feet, concrete lined.
Tunnel #29 – At Mile Post 135.9 on the 1912 line, it is West of East Applegate. Length is 1,009 feet, of which 405 feet is concrete lined, 604 feet is timber posts between concrete ribs.
Tunnel #30 – At Mile Post 138.7, on the 1912 line West of Colfax. Length is 780.33 feet, of which 720.33 is concrete lined, 60 feet gunite only.
Tunnel #31 – At Mile Post 139.2, on the 1912 line West of Colfax. Length is 443.66 feet, of which 109.50 feet is concrete lined, 334.16 gunite lined with steel bents.
Tunnel #32 – At Mile Post 139.4, length is 769.33 feet, concrete lined.
Tunnel #33 – At Mile Post 144.9, built as double track in 1913. Now used only as Westbound. Length is 1331 feet. East Bound rails go around Cape Horn.
Tunnel #34 – At Mile Post 145.1, built as double track in 1913; now only used as Westbound. Length 410 feet, concrete lined.
Tunnel #35 – At Mile Post 176.6, built on the double tracking line of 1924 West of Shed 10. Length is 737.66 feet, of which 263.66 is concrete lined, 474 feet is unlined. NOTE: In the double tracking of 1913, Colfax to Blue Canyon, Tunnel No. 1 was initially called Tunnel #35, but was renumbered to Tunnel #1 (See Track #1 Schedule, above).
Tunnel #36 – At Mile Post 176.9 on the 1924/1925 line, double tracking West of Shed 10. Length is 325.66 feet, concrete lined.
Tunnel #37 – At Mile Post 177.8 on the 1924/1925 double tracking line, West of Shed 10. Length is 410.66 feet, of which 340.66 feet are concrete lined, 70 feet unlined.
Tunnel #38 – At Mile Post 180.5 on the 1924/1925 line East of Cisco. Length is 920.66 feet, of which 543.66 is concrete lined, 377 feet unlined.
Tunnel #39 – At Mile Post 180.9, on the 1924/1925 line. Length is 279.66 feet, concrete lined.
Tunnel #40 – At Mile Post 185.3, on the 1924/1925 double tracking line, West of Troy. Length is 315.66 feet; 183.66 is concrete lined, 132 feet unlined. This tunnel was daylighted between January 1, 1976 and January 1, 1978.
Tunnel #41 – At Mile Post 193.3 on the 1924/1925 double tracking line East of Norden. Length is 10,325.66 feet, of which 6,171.66 feet is concrete lined, and 4,154 is unlined. This tunnel is known as THE BIG HOLE. This Tunnel is now used in place of the Tunnels and Snow Sheds visible from I-80 between Truckee and the Summit.
Tunnel #42 – At Mile Post 200.1 on the 1924/1925 double tracking near Andover. Length is 892.83 feet, concrete lined.
Above information from Southern Pacific Transportation Company Tunnel Data dated June 1, 1984, and John R. Gillis, CPRR Civil Engineer, paper read to the ASCE on January 5, 1870.
Credit: List of CPRR Tunnels based on notes provided by Lynn D. Farrar.