When Thistle Vanished
F. Hol Wagner Jr.
(from Trains magazine, July 1983, pages 14-18; used with author's permission)
(See also: Utah Geological Survey's publication UGS Survey Notes, v. 37 no. 2, May 2005)
On Thursday, April 14, 1983, a moisture-saturated clay mountainside on the south side of Spanish Fork Canyon, 20 miles southeast of Provo, Utah, began to slide . . . just below (to the northwest) the tiny (population 45) railroad town of Thistle junction of the Denver & Rio Grande Western's main line with its 130-mi1e Marysvale Branch to the south, and junction of U.S. Highways 6 from the east and 89 from the south. The state estimates that 4300 highway vehicles and 20 freight trains traverse the Wasatch Mountains pass a day. Initially, the massive subsidence--slow but steady--had the effect of heaving the railroad, the bed of the Spanish Fork River, and the combined U.S. 6-89, upward some 10 to 15 feet. In an effort to halt the slide, the Rio Grande hired H-E Lowdermilk Construction Co. of nearby Helper, Utah, to remove a portion of the hillside in the narrow section of the canyon. But the effort was unsuccessful, and by that afternoon the sliding mountain-reacting to years of water accumulation-was pushing material up against the sheer rock wall across the river.
Rio Grande's westbound train 17, the Rio Grande Zephyr (scheduled to be replaced by Amtrak's California Zephyr 10 days later), running late, passed through Thistle and gingerly treaded the shifted track across the slide area late Thursday evening after waiting for an eastbound empty coal hopper train to clear. The RGZ would be the last train through for months.
By 1 a.m., now Friday, April 15, the rising river water had inundated the highway and the tracks, forcing their closure. Not only was the D&RGW affected, but so was the coal-hauling Utah Railway, which shares the Rio Grande main line (Utah has trackage rights from a junction just above Helper to Thistle and owns one of the two main tracks from Thistle to Provo).
Rio Grande track crews immediately began removing track and switches up the canyon. The Marysvale Branch, which follows Thistle Creek south, was also submerged, as was U.S. 6 to the east. All residents of Thistle-22 families-were evacuated, and by Monday, April 18, the entire town was under water, with only a few rooftops visible here and there.
Workers and heavy equipment of the Rio Grande, the Utah Department of Transportation (UDOT), Utah County (Provo), and four private contractors labored feverishly to stem the steady advance of the mountain, but it was a losing battle. By Monday morning, the slide, advancing at the rate of 3 feet per hour, had buried the canyon with the creation of a natural dam some 600 feet wide and 50 feet high. The dam continued to grow, and water depth behind it reached 80 to 85 feet. The railroad subsequently estimated that 3.3 million dollars' worth of its equipment and property were lost underwater.
The Rio Grande Zephyr, trapped in Salt Lake City, detoured home to Denver over the Union Pacific via Laramie on Friday, April 15, with UP GP40X 9003 (UP requires cab signals on lead units) piloting the Grande's F9's. The RGZ finished out its D&RGW career running as a Denver-Grand Junction (Colo.) turn, with the railroad providing bus service between Grand Junction and Salt Lake City, via Salina.
On Monday morning, April 18, Rio Grande officials announced an embargo on all westbound traffic originating between Denver and Thistle. Fortunately for the Grande, most of the coal mines it serves in Utah are located in Carbon and Emery counties, east of the slide, and a vast majority of their coal travels' east to market and is thus unaffected by the embargo. The Utah Railway (now, incidentally, all-EMD by virtue of leasing UP SD40's and storing all its Alcos) was not so fortunate--its markets to the west were totally isolated from the four major on-line mines. Dumayne Gilson, executive vice president and chief operating officer of the Utah, held off until Tuesday, April 19, before reluctantly calling an embargo and laying off 75 of the road's 90 employees. Normally, the Utah transports 250,000 tons of coal a month to points west of the slide, and the railroad could continue to serve the mines only if the shippers would agree to pay the additional freight for shipping coal east to Denver over the D&RGW, then back west to Utah over the Union Pacific. The mines have found truck haulage west to the UP in Utah to be cheaper, although not nearly as much coal is being moved. Also affected and shut down: the 11-mile Carbon County Railway, a U.S. Steel subsidiary which hauls coal to a D&RGW interchange at Columbia Junction, destined for USS's Geneva Works at Orem, Utah, north of Provo. Geneva-bound coal of USS mine at Somerset, Colorado, is taking an 1100-mile D&RGW-UP-D&RGW circuit to destination via Denver vs. usual 100-mile all-D&RGW routing, with the Grande absorbing cost difference.
The Rio Grande, which as a result of the Union Pacific-Missouri Pacific-Western Pacific merger accord last year had just begun receiving a guaranteed 100,000 cars a year (or about 800 a month) of interchange traffic from Southern Pacific through the Ogden Gateway, found itself forced to detour all its through traffic over the UP between Ogden/Salt Lake City and Denver. This marks the first time anyone could recall the Grande detouring over the UP, and was an ironic reversal of the aftermath of the infamous blizzard of January 1949, when UP became snowbound in Wyoming and had to detour Salt Lake-Denver on the Rio Grande for over a week.
When it became obvious that the Thistle slide could not be stopped, stabilizing and strengthening it became the primary concerns. Men using heavy equipment worked continuously to shape the steadily moving material, and rock from the cliffs above was blasted down to help solidify the dam/slide, in the hope of preventing it from giving way and possibly flooding portions of the town of Spanish Fork (population 9825) 12 miles downstream. All the while, engineers were searching for a way to drain the slowly enlarging reservoir behind the natural dam (promptly dubbed Lake Thistle). As the slide finally slowed late in the week and appeared to have reached its maximum size, a new concern was the possibility of the rising water topping the dam and beginning to erode it.
Initially, corrugated metal pipe was utilized in an effort to drain, or at least prevent further water accumulation in the reservoir. But the still-advancing slide quickly crushed the pipe. Next, a 200-foot stretch of never-completed railroad tunnel, dug by the Utah Railway years ago, was considered as a starting point for the drain tunnel to be bored around the slide. The abandoned tunnel headed in the wrong direction to help, however, so that plan was quickly dropped.
By Friday, April 22, engineers had decided to drill an overflow, or spillway, tunnel 500 feet long at a level about the still-rising water (6 days later, on April 28, it was 100 feet deep and rising at a half inch per hour). This tunnel, expected to be completed in short order, would prevent the water level from rising any more behind the dam. A 1500-foot-long tunnel around the slide was considered, to permanently drain Lake Thistle; this tunnel would have become the new channel of the Spanish Fork River, allowing the slide to eventually be stabilized and reshaped to allow the highways to be rebuilt. But the U.S. Army Corps of Engineers, brought in to take charge of draining the lake, decided instead to pump the lake dry. On May 2, a 1.7-million-dollar contract was awarded to Weyher Livsey Construction Co. of Salt Lake City to perform the work, expected to take 3 full months of round-the-clock pumping.
The Rio Grande, however, was not about to wait the many months it might take for the slide to become stabilized-and there is no guarantee it will remain stabilized. Indeed, the Grande immediately began seeking a new route around the slide area. The only practical one is close, but the track will be deep inside the mountain across the canyon, and at an elevation considerably above the original grade. From west to east, the proposed new alignment--which will have a maximum 2 per cent grade, same as on the present line up toward Soldier Summit--will run a short distance north up Diamond Draw to begin gaining elevation, then double back and follow a contour high on the north side of Spanish Fork Canyon. Since it's "inside the curve" from the old alignment, the new route will be somewhat under a mile shorter than the flooded one. As the tracks approach the cliffs opposite the landslide, they will turn into a curving, approximately 3000-foot-long tunnel through Billies Mountain and emerge again in Spanish Fork Canyon high above Thistle itself; the tunnel will be about halfway along the 6-mile new alignment. A gradual descent will then be made back to the existing grade, east of the upper limits of Lake Thistle and about 3 miles from the old junction. A single track will be built first, with the grade having double-track capability; assuming two tracks through Billies Mountain eventually, the second tunnel would be about 50 feet inside the hill from the first new bore. Most of the land D&RGW had to utilize is privately owned.
In late April, the Grande obtained a tunnel-boring "mole" from Morrison-Knudsen, the Boise (Idaho)-based construction company. The mole, located in New Hampshire, was trucked (!) to the site in four loads totaling 410,000 pounds, via Interstate Highways 80, 76, and 70. The Grande hoped to be able to have the tunnel drilled in 45 days and aimed at reopening its line by July 1. "We can't build the train tunnel until we build the diversion tunnel," explained Bob Nance, D&RGW general manager. "The diversion tunnel will stabilize the level of the lake so the train tunnel won't be flooded. Hopefully, we will be building the tunnels in conjunction with the state or Federal government. We don't really care; we just need the tunnels built." In early May, the three affected counties-Carbon, Emery, and Utah-were designated Federal disaster areas to facilitate help.
Railroads were not the only land transportation greatly affected by the slide, for U.S. 6 is the only direct link from the coal country around Price and Helper (Emery/Carbon County population over 25,000) to Provo and Salt Lake City (120 miles). UDOT issued a press release specifying three detours: 172 miles via Duchesne (but with grades of up to 8 per cent); 189 miles via Highways 132 and 31 (but restricted to vehicles under 10 tons); 243 miles via Salina (with no major obstacles for big trucks).
At best, construction of the Rio Grande's new railroad grade to the tunnel site and actual tracklaying were expected to extend completion of the project well into the summer. Meantime, Rio Grande freight traffic and Amtrak's newly renamed California Zephyr continued to detour through Wyoming on the UP. Amtrak provided bus service across Colorado and Utah to all former RGZ stops except Granby and Bond, Colorado, and Helper, Utah, and issued an interim schedule to cover its former Overland Route stops in Wyoming (plus Greeley, Colo,), suddenly given a reprieve from their removal from the Amtrak system. And, because of the shorter running time over UP than D&RGW, yet wanting to adhere to its published CZ schedule, Amtrak was having the Superliner train layover in Denver to take up the slack ... and even offering, at a nominal fee, Gray Line bus tours of Denver to westbound passengers in the morning!