COAL ISN’T DEAD After racing down Logan Hill, BNSF Railway coal train C-NAMCDJ rolls by the distributed power of train C-WTMMIC in Bill, Wyo., on the Orin Line. Track 4, which was added during the peak Powder River Basin year of 2008, is now occupied by stored hoppers rendered surplus by the downturn in volume. 11 TrainsMag.com Wyoming’s Powder River Basin is still the bustling center of American coal traffic. But it is fading Story and photos by Bill Stephens STORM CLOUDS GATHER T he sun is rising over the Powder River Basin just north of Bill, Wyo., where you’re wondering if your eyes are playing tricks on you. You’re overlooking a long straightaway on the quadruple- track section of the Joint Line, over which BNSF Railway and Union Pacific still send dozens of coal trains each day. The tracks swing to the left, and you trace their path up a ridge that’s nearly 6 miles away as the crow flies. And you’re pretty sure, near the top of the ridge, you see two dark smudges moving down Logan Hill behind a pair of headlights. Sure enough, it’s not one but two BNSF coal trains racing down the 1% grade. The train on the far track has a 30-car lead as they descend the hill, but the train on the closer main is gaining ground. Over the next 7 minutes the question of the faster train will get sorted out on the 4 miles of undulating tangent track leading to the Highway 59 overpass where you stand. In the end, it’s not even close. Train C-WTMMIC, which originated at Black Thunder mine’s west loadout and is bound for the Comanche Generating Station near Pueblo, Colo., roars by on Track 3. It’s a train length ahead of the C-NAMCDJ, which is on Track 1 with loads that originated at North Antelope Rochelle Mine for the Dave Johnston Power Plant near Glenrock, Wyo. Meanwhile, a green signal on Track 2 beck- ons an empty BNSF coal train that will cruise between the loaded trains on its way back to the mines. This scene sums up the Powder River Basin today: North America’s largest coal field is still a busy place, but not hopping like it was during its heyday. Volume in 2020, measured by trains per day, is less than half of what it was at the 2008 peak. In the years leading up to 2008, BNSF and UP were struggling to nearly 90 loaded trains per day out of the Powder River Basin and were feeling the heat from utilities, reg- ulators, and Congress. So the railroads com- pleted triple-tracking the entire 103-mile Joint Line that serves the majority of PRB mines and added a 21-mile stretch of qua- druple track over Logan Hill. It was the cul- mination of four decades of nearly continu- ous investment in capacity that enabled the railroads to haul more than 400 million tons of coal off the Joint Line annually. There were predictions that PRB mines would pro- duce 500 million tons per year by 2012 and IN THE YEARS LEADING UP TO 2008, BNSF AND UP WERE 12 MARCH 2021 A Union Pacific coal train has snaked its way from Antelope Mine to Converse Junction, where it awaits a fresh crew. Antelope Mine, now owned by the Navajo Nation, is the southernmost mine in the Powder River Basin. A Union Pacific crew lifts the 141-pound welded rail off Track 3 on Myles Hill east of Shawnee, Wyo., on its Powder River Subdivision in October 2020. This was the last coal capacity UP added to its system — and the first to come out. 600 million tons by 2025, which would have added 41 loaded trains per day to the Joint Line. But that was a dozen years ago, when no one foresaw how fracking, low-cost natural gas, and climate change concerns would upend coal. Powder River Basin coal vol- umes declined slowly at first, but the drop has only accelerated since 2016. “It wasn’t just a change in tides,” a former railroad executive says. “The entire ocean moved!” Indeed it did: PRB coal production in 2020 was on a pace to fall to 205 million tons, approaching levels last seen in 1993. The signs of decline are everywhere you look during an October 2020 visit. North of Bill, surplus coal trainsets occu- py several miles of Track 4. Protected by centralized traffic control and built with heavy 141-pound rail that rests on concrete ties anchored in deep ballast, the fourth main was intended to keep coal trains mov- ing, not store them. In yards along BNSF’s coal-dependent routes — Alliance, Neb., Edgemont, S.D., and Donkey Creek, Wyo. — hundreds of locomotives once assigned to PRB service sit idle. They’re unlikely to ever rumble again over the demanding hill-and-dale profile of the Joint Line with coal trains destined for power plants in Texas, the Midwest, and as far away as Georgia. And on UP’s Powder River Subdivision just east of Shawnee, Wyo., a crew is lifting the rails from the now unnecessary 15 miles of third main track that during the peak years kept traffic fluid on Myles Hill. It was the last piece of coal capacity UP added to its network and the first to come out. More track will almost certainly be removed in the years ahead, as BNSF and UP simply have more capacity than they need to handle dwindling volume. No one has yet waved a white flag of sur- render, but coal has lost the competitive bat- tle as a utility fuel. Abundant natural gas re- mains far cheaper and is increasingly the fuel of choice for electricity generation. New renewable energy projects are elbowing coal aside, including the 160-turbine Cedar Springs wind farm built alongside the Joint Line south of Bill. And more coal-fired pow- er plant retirements loom. The killer stat: The share of electricity produced from coal, which stood at 48% in 2008, fell below 20% in 2020, according to the U.S. Energy Infor- mation Administration. VERY DEFINITION OF HEAVY HAUL The railroad world has never seen any- thing like the Powder River Basin and its concentration of surface mines. The coal fields stretch across northeastern Wyoming and into neighboring Montana, with 16 mines that produced 43% of the nation’s coal in 2019, according to the EIA. BNSF serves the entire PRB, including four mines north of Gillette, Wyo., and another four in Mon- tana. But the heart of the PRB is the 50-mile stretch of the BNSF/UP Joint Line that serves eight mine complexes located be- tween Caballo Junction on the north (Con- trol Point 15, measured from Gillette) and Converse Junction (Control Point 65) on the south. Among these Southern Powder River Basin mines: North Antelope Rochelle and Black Thunder, whose combined output at five loadouts is an astounding 25% of all of the coal produced in the U.S. With its lines encircling the PRB, BNSF coal traffic can exit the Joint Line to the north via Gillette and to the south via Orin, Wyo. From the north end of the basin, BNSF’s coal runs to the junction town of Al- liance, Neb., via Edgemont, S.D., and Craw- ford, Neb. From Alliance, the traffic can 13 TrainsMag.com After a crew change, a BNSF Railway coal train prepares to depart Edgemont, S.D., in October 2020 alongside a long line of stored power. BNSF also has parked hundreds of locomotives at coal-related yards in Alliance, Neb., and Gillette, Wyo., due to the coal downturn. Converse Jct. Converse Jct. West Bill East Bill Crossover 74 (East Logan) Crossover 74 (East Logan) Crossover 91 Crossover 95.5 Crossover 103.6 (West Walker) Crossover 110.6 Crossover 8.2 Donkey Creek Jct. Caballo Jct. Belle Ayr Jct. Rojo Jct. Cordero Jct. Nacco Jct. Campbell Reno Jct. Reno Jct. Shawnee Jct. Shawnee Shawnee Crossover 45.7 Crossover 45.7 Crossover 49.2 Crossover 49.2 Crossover 55.8 Crossover 55.8 Bridger Jct. East Fisher East Fisher Thunder Jct. GILLETTE Coal Creek Jct. Orin DOUGLAS DOUGLAS N 90 90 25 25 © 2021 Kalmbach Media Co., TRAINS: Bill Metzger and Tom Danemann GILLETTE Bill Reno Jct. Shawnee Jct. Orin Wendover Guernsey Joyce Bridgeport Alliance Chadron To Rapid City Crawford Crandall Lusk Edgemont Newcastle Donkey Creek Scottsbluff Northport BNSF to Cheyenne DOUGLAS BNSF RCPE RCPE UP UP UP UP UP BNSF BNSF BNSF BNSF BNSF BNSF NEBKOTA W Y O M I N G WYO. N EB . S .D. N E B R A S K A Map area N. Platte River BNSF/UP Joint Line BNSF Orin Sub BNSF Orin Sub Coal mine Private trackage (each mine owns its own trackage) Antelope North Antelope Rochelle Black Thunder South Black Thunder Black Thunder West Coal Creek Cordero Cordero Rojo Belle Ayr Caballo 18 20 95 59 387 450 59 59 91 94 50 51 Antelope Creek UP to North Platte, Neb. BNSF to Laurel, Mont. BNSF to Guernsey 0 10 miles Scale BNSF to Edgemont, S.D. BNSF to Huntley, Mont. BNSF to Huntley, Mont. To Eagle Butte B e l l e F o u r c h e R i v e r Hilight Rd. Steckley Rd. POWDER RIVER BASIN, WYO. either head to points in the Midwest and Southeast via Lincoln, Neb., or head south to Texas and Colorado via Northport, Neb. Almost all BNSF coal that exits the basin via Orin runs southeast to Northport. From there it either turns south for Colorado and Texas or, if bound for the Midwest or South- east, swings north to Alliance. (Just 2% of the PRB’s coal heads for export, all of it at Roberts Bank, British Columbia, part of the Vancouver port complex.) The entire Powder River Basin operation — from mine to main line to power plant and back — is a model of efficiency on a massive scale. At the mines, mammoth dragline cranes remove soil to expose over- burden, the earth and rock that covers seams of coal that are hundreds of feet thick. The mine faces are blasted away, sending plumes of smoke skyward, and the coal is scooped into yellow dump trucks the size of a house. The trucks roll out of the man- made canyons to preparation plants or di- rectly to loadout silos that are as tall as a 20-story skyscraper. When an empty train arrives on mine trackage, the Class I railroad crew steps off and a contract engineer climbs aboard. In not much more than an hour after the lead units pass beneath the loadout at 2 mph, the train is filled with any- where from 15,616 to 17,080 tons of coal. The consist rolls around a loop track and is ready to depart once a fresh BNSF or UP crew is back at the controls. RISE AND FALL The rise of PRB coal began four decades ago and has shaped Western railroading ever since, from the construction of new lines to becoming a proving ground for A.C. traction and distributed power that is now the industry standard. Rob Godby, an economics professor who is deputy director of the University of Wyo- ming’s Center for Energy Regulation and Policy, says the success of Powder River Basin coal rested on three long-term trends. First, the energy crisis of the early 1970s sent the country looking for alternatives to im- ported oil, and coal was seen as a way to re- duce reliance on foreign sources of energy. Second, federal regulations designed to reduce the environmental toll of acid rain favored the basin’s low-sulfur coal, which soon displaced Appalachian coal at many power plants. Third, the deregulation of rail- roads under the 1980 Staggers Act increased competition and boosted the industry’s pro- ductivity, making it cost-effective to haul the basin’s coal to faraway destinations. “You put those three things together and you have the perfect opportunity in the Powder River Basin,” Godby says. From the 1970s to 2008, volume only moved in one direction: upward. Wyoming coal production passed the 100-million-ton mark in 1981, 200 million in 1993, 300 million in 1998, and 400 million in 2005. In 2008, the Cowboy State’s coal tonnage POWDER RIVER BASIN AVERAGE LOADED TRAINS PER DAY BNSF Railway Union Pacific Total % change from peak 2008 53.7 36.2 89.9 NA 2015 48 24.1 72.1 -20 2016 43.4 20.2 63.6 -29 2017 43.8 20.2 64 -29 2018 41.1 18.8 59.9 -33 2019 37.9 16.1 54 -40 2020 28.9 12.3 41.2 -54 Source: U.S. Surface Transportation Board Note: 2008 is full year daily average. 2015 through 2020 is average for August, typically the peak month for PRB coal loadings. IN 2008, THE STATE’S COAL TONNAGE PEAKED AT 466 14 MARCH 2021 peaked at 466 million tons — enough to fill nearly 33,000 trains. Now coal faces three big problems, Godby says: competition from cheap natu- ral gas and renewables, ongoing retirement of coal-fired power plants, and the poten- tial for regulation of greenhouse gas emis- sions to fight climate change. Fracking for oil and natural gas hit criti- cal mass just as Powder River Basin coal peaked and the Great Recession arrived. At the time, coal’s 2009 decline was chalked up to reduced electricity demand as the economy faltered. The reality, Godby says, was that natural gas was beginning to eat coal’s lunch. “That’s the earth-shaking moment,” he says. And it’s not just that natural gas itself is cheaper than coal on a BTU basis. [The British Thermal Unit is a standard measure of energy.] A gas-fired power plant is far less expensive to build and operate than a coal-fired plant. Plus, natural gas produces half the greenhouse gas emissions of coal. 15 TrainsMag.com A BNSF Railway conductor heads back to his loaded coal train as an empty train, left, passes near Mullen, Neb., on the aptly named Sand Hills Subdivision in Western Nebraska. This is September 2020, and the torrent of PRB coal that once passed here has been reduced greatly. Bound for Black Thunder Mine in October 2020, a BNSF Railway empty hopper train eases off the Joint Line onto the Reno Subdivision that serves Arch Coal’s Black Thunder and Jacobs Ranch mines, which are operated as a single complex. In the background: Black Thunder’s west loadout, which was opened in 2008. Renewable energy sources, such as wind and solar, are now cheaper to build and op- erate than even natural gas plants in most parts of the country, Godby says. Although there are not yet regulations governing car- bon dioxide emissions, many utilities be- lieve there will be. Coal’s higher costs have sped up the pace of retirements, and regu- latory uncertainty has put an end to coal power plant construction. “You put those together and coal is in big trouble,” Godby says. “It starts with economics but has this cloud of uncertainty over it.” Overall U.S. coal-fired generating ca- pacity peaked in 2011, according to the EIA, and through 2020 had fallen by more than a third as coal power plants were retired or converted to burn natural gas. Last year, before the pandemic reduced demand for electricity, UP CEO Lance Fritz said the railroad’s coal traffic had hit bottom. “We think that what you’re seeing right now is all about natural gas below $2. Once you’re in that ballpark, only the most efficient coal electricity generating units are fired up. And there’s precious few of them left today.” All this is shrinking the potential mar- ket for PRB coal. The top five destinations for Powder River Basin coal are Texas, Mis- souri, Illinois, Wisconsin, and Arkansas. In the Lone Star State, by far the top receiver, coal produced 40% of electricity in 2010, according to the Electric Reliability Coun- cil of Texas, which manages the state’s pow- er grid. Through the first eight months of 2020, coal was responsible for just 17% of the state’s electricity, trailing natural gas (41%) and wind (23%). Similar trends have played out in the other top destinations for PRB coal. Analysts say PRB coal volume may inch upward in 2021 due to rising gas prices and greater electricity demand, but the long-term direction will be down. A TALE OF TWO RAILROADS BNSF and UP have responded to the decline of coal in different ways. UP focus- es more on profit margins and BNSF favors volume, says Allison Landry, an analyst with Credit Suisse. Last year Fritz said the railroad empha- sized “judicious pricing” of its traffic to earn an acceptable return. It’s a strategy UP began in the early 2000s so that its rates could support reinvestment in coal routes and equipment. In the boom years, UP was able to capture both rate and vol- ume increases. But the decline of UP’s coal volume after 2008 was accelerated by loss of market share to BNSF. More than half of UP’s 9% decline in Powder River Basin volume in 2013, for example, was due to a contract loss. The trend contin- ues: In January 2021, BNSF began deliver- ing coal to Omaha Public Power District’s Nebraska City Power Station, amounting to a train or two per day that used to ar- rive behind Armour Yellow locomotives. BNSF has been flexible on rates, in some instances tying them to natural gas prices when reduced transportation costs could prevent a coal plant from shutting down. The other thing driving BNSF’s ap- proach: putting as much volume as possible over its coal routes to make the most of the $3.3 billion sunk into the Powder River Ba- sin and other coal lines, locomotives, and trainsets between 1994 and 2008. “BNSF expects coal volumes will contin- ue to decline over time with increased com- petition from natural gas and renewable energy sources,” spokeswoman Amy Casas says. “As we have always done, we will con- tinue to work with our coal customers to capture any market opportunities that may arise and remain flexible to their needs.” The results of the divergent strategies show up in the railroads’ coal volumes. Combined, they moved 54% fewer loaded trains per day out of the Powder River Ba- sin in August 2020 compared to the daily average in 2008, according to Surface Transportation Board data. But UP’s daily train count is down by 66%, while BNSF’s is off by 46%. As overall coal revenue has fallen, both railroads have taken steps to cut related op- erating costs. The most visible examples are “BNSF EXPECTS COAL VOLUMES WILL CONTINUE TO DECLINE OVER TIME WITH 16 MARCH 2021 A pair of GEs lead a Union Pacific loaded coal train over the Joint Line’s undulating terrain south of Bill, Wyo., in October 2020. doubling up empty trains and, in a few cases, even running double-length loaded trains for part of their journeys. Coal shippers say the cost savings are not passed along to them. And tying one train to the back of another can create headaches. “The doubled up trains can be from different shippers. This has, on occa- sion, caused them to send the wrong train to load at a mine once they’ve uncoupled them,” says Bette Whalen, president of the Western Coal Traffic League, an associa- tion of consumers of coal produced west of the Mississippi. TOO LITTLE TRAFFIC, TOO MUCH TRACK Fifteen years ago, the Joint Line — offi- cially BNSF’s Orin Subdivision — was bursting at the seams. For more than a year, neither BNSF nor UP could keep up with utilities’ insatiable demand for PRB coal. In fact, they fell 20 million tons short of their coal delivery commitments in 2005 and faced lawsuits from utilities. The railroads’ job was made tougher when coal dust, blown off loaded gondolas, worked its way into the roadbed and com- bined with snowmelt and heavy rainfall to weaken the track structure. The Joint Line in 2005 was plagued by a spate of derail- ments and maintenance windows neces- sary for rebuilding the damaged roadbed. Congestion around mine loadouts rippled across both railroads’ coal networks. As mine-power plant-mine cycle times length- ened, utility officials looked at their dwin- dling coal stockpiles and feared they’d have to shut down power plants until more trains arrived. This prompted utilities to put more coal sets into service, which worsened the railroads’ downward spiral of congestion. “The slower the cycles got, the more sets the utilities put in. The more sets they put in, the slower the cycles would get,” one operat- ing official recalls. As a result, utilities, federal regulators, and Congress called both railroads on the carpet. BNSF and UP knew they needed to add capacity, and add capacity they did: Between 2006 and 2008 they spent $200 17 TrainsMag.com At the south end of the Joint Line, a BNSF Railway coal train climbs Walker Hill, with a new wind farm under construction in the background, in October 2020. The rapid development of wind power has helped cut the need for Powder River Basin coal in Texas and the Midwest. million to finish the remaining 25 miles of triple track and add 21.1 miles of fourth main. Together, these projects increased Joint Line’s simulated capacity by 16%, which was right in line with tonnage growth. About a dozen landing spots were added at mines, too, freeing up precious mainline capacity. The additional steel came just in time. The Joint Line’s peak day — Nov. 30, 2008 — arrived 165 days after the final section of quadruple track entered service. On that record day, 84 trains were loaded at Joint Line mines, with the route carrying a total of 168 trains when inbound empty move- ments are included. It was an exclamation point on a record month: In November 2008, the Joint Line handled an average of 73 loaded trains per day, or a total of 146 trains in 24 hours. Collecting dust somewhere in railroad headquarters in Fort Worth and Omaha are separate plans that would allow BNSF and UP to haul 500 million tons of coal — and ultimately 600 million tons — out of the Southern Powder River Basin annually. The Joint Line plans envisioned more fourth main track, more mine trackage, and expanding UP’s Bill Yard. The volume never materialized. Fast forward a dozen years and with Joint Line mines loading between 22 and 37 trains per day, neither railroad has enough coal traffic to fill its routes. UP’s coal overcapacity problem is more focused than BNSF’s. UP’s 271.5-mile line leading out of the PRB — the Powder River and South Morrill subdivisions linking Shawnee Jct., Wyo., with the Overland Route at O’Fallons, Neb. — is a first-class railroad that at its peak handled 77 trains per day. Today this double-track route with CTC sees fewer than 24 trains per day. And the 107-mile Powder River Subdivision, 62 miles of which was built from scratch in 1984, is utterly dependent on coal. BNSF faces a different overcapacity dilemma. It enjoys triple UP’s coal volume, but outside of the Joint Line those trains roll over about 1,950 miles of railroad where coal traffic dominates. The primary coal ar- teries have long sections of double track — and they’re still busy. You can drive Nebras- ka Route 2 alongside the 236.3-mile Sand Hills Subdivision from Ravenna to Alliance, for example, and see a baker’s dozen of coal trains between breakfast and lunch. Yet both railroads still face the same question: What do you do with an under- utilized railroad? The answer is not as simple as it may seem. BNSF and UP both reap operational benefits from having plenty of capacity. Trains don’t encounter congestion in coal country, and they cycle between mines and power plants faster than they otherwise would. So the railroads can use fewer coal trainsets, locomotives, and crews, and save fuel in the process. These operational cost savings need to be weighed against ongoing track-maintenance spending, the tab for removing track, and the benefits of using lifted rail and ties elsewhere. At some point, though, railroads are 18 MARCH 2021 A BNSF Railway merchandise train cruises along the Joint Line at Reno Junction, Wyo., while a Union Pacific train creeps toward the Black Thunder west loadout in October 2020. It would have been unheard of for merchandise traffic to appear on the Joint Line during coal’s heyday. There was no room for it. “AS THE MOVEMENT OF COAL CONTINUES TO DECLINE, WE WILL likely to rationalize their coal line trackage. They have three options for slimming down. The first is a mothball strategy: On double-track routes, pull out of service one main track between certain crossovers, es- sentially creating a single-track railroad. On single-track routes, retire some sidings. The second option is to take up sections of second main track or some passing sidings. The third option — concentrating coal traf- fic on one railroad’s line, and downgrading or abandoning the other — is where things get complicated in a hurry. For several years UP has asked BNSF if it would be interested in sending its Pow- der River Basin traffic over UP rails from Shawnee Junction to Northport, Neb., or even all the way to Grand Island, Neb. UP and BNSF lines intersect at both points. This could save BNSF mileage and grade on at least some of its traffic, while better utilizing UP’s capacity. BNSF has said no thanks. While BNSF’s lines radiating out of the PRB are reliant on coal, they to varying degrees also carry or originate other types of traffic. And Fort Worth simply cannot stomach moving its much larger coal volume over its rival’s rails. Another option the railroads could con- sider — assuming they want to cooperate — is directional use of their existing lines between Shawnee Junction and Northport, with one railroad handling loads and the other carrying empties. EFFECTS OF COAL BOOM LINGER If there’s a silver lining in the decline of coal, it’s all of the capacity the railroads built outside the PRB during the boom years. The growth of coal helped fund the installation of second and third main tracks, additional passing sidings, bypass tracks, and CTC across the Midwest to and including Texas. Now BNSF and UP can use that capacity to better move intermodal and merchandise trains and attract and retain more service-sensitive traffic. On UP, all the investment east and south of North Platte, including the 110 miles of triple track east to Gibbon Junction, Neb., benefits the railroad’s mix of intermodal, manifest, and bulk traffic. On its former Chicago & North Western main line across Iowa, for example, UP’s improvements in- cluded restoring 32 miles of second main track between Denison and Missouri Valley and completing 209 miles of CTC. The challenge is to keep carload and in- termodal traffic growing to replace coal. “It seems like there is the opportunity for the Western rails to be able to offset the coal decline,” Landry says. BNSF in 2016 launched intermodal ser- vice linking the Pacific Northwest with Texas. The trains take an unlikely shortcut: the Orin Subdivision, which now sees manifest traffic, too. “As the movement of coal continues to decline, we will keep looking for ways to better leverage our network,” BNSF’s Casas says. Low natural gas prices that have under- mined coal have been a boon to UP’s pet- rochemical traffic, Fritz notes. Plastics pro- duction, fueled by low-cost natural gas, is expected to grow for the next decade on the Gulf Coast of Texas and Louisiana, where nearly two dozen new chemical plants have been built or expanded in re- cent years. While chemical traffic growth won’t offset the coal volume loss, from a revenue standpoint it won’t have to. A carload of chemicals brings UP 60% more revenue than a load of coal. The windswept grasslands of eastern Wyoming remain the Big Show for coal railroading in North America. No one knows when the curtain will come down. For now you can still witness the show in places like Belmont, Neb., summit of 1.55% Crawford Hill, where BNSF coal trains emerge from the deep cut with the lead units working their hearts out. The loads trundle by you at perhaps 15 mph, fol- lowed by bellowing distributed power units and a pair of Crawford-based helpers. The helpers cut off on the fly and glide to a stop. Once they get the signal, they’ll slip through the crossover and head back down the hill to await the next train. “Coal kept the lights on for almost all of the 20th century. It’s going to continue to keep the lights on for a little while longer,” Godby says. “If there’s ever a day when the last coal train leaves the station, it will prob- ably be from the Powder River Basin.” 19 TrainsMag.com A BNSF Railway coal train crests Crawford Hill in Belmont, Neb., behind a pair of SD70ACes in September 2020. Two distributed power units on the rear are assisted by a pair of Crawford-based helpers that will cut off on the fly, reverse direction, and cross over for the trip down the hill. Reproduced with permission of copyright owner. Further reproduction prohibited without permission.