1 00:00:01,667 --> 00:00:05,100 [narrator] In Poland, an elite team of engineers is embarking on 2 00:00:05,267 --> 00:00:06,968 a mega construction project. 3 00:00:08,167 --> 00:00:11,801 They are building a new super railway to open up the south of 4 00:00:11,968 --> 00:00:14,000 the country like never before. 5 00:00:15,801 --> 00:00:18,767 The team must build hundreds of complex structures, 6 00:00:20,000 --> 00:00:22,801 tunnel through some of the most challenging terrain in Europe, 7 00:00:24,467 --> 00:00:26,267 and battle treacherous geology... 8 00:00:33,100 --> 00:00:35,968 ...to establish this critical transportation line. 9 00:00:37,000 --> 00:00:39,200 [speaking Polish] 10 00:00:43,501 --> 00:00:44,834 This mountain railway... 11 00:00:45,868 --> 00:00:50,100 ranks in a league of ambitious new engineering wonders that 12 00:00:50,267 --> 00:00:53,167 are bigger, faster, taller, 13 00:00:53,334 --> 00:00:55,400 and more advanced than anything 14 00:00:55,567 --> 00:00:57,701 ever constructed before. 15 00:00:57,868 --> 00:01:01,701 This is the inside story of the extraordinary challenge 16 00:01:01,868 --> 00:01:04,167 of building these giants. 17 00:01:15,267 --> 00:01:18,067 Southern Poland is a region of natural wonders, 18 00:01:20,200 --> 00:01:21,501 but it is one of the hardest regions 19 00:01:21,667 --> 00:01:22,968 in the country to cross. 20 00:01:24,968 --> 00:01:28,701 Between Krakow and the towns of the Carpathian foothills, 21 00:01:28,868 --> 00:01:31,267 railways follow routes laid more than a century ago. 22 00:01:32,667 --> 00:01:33,734 [train whistle blows] 23 00:01:34,868 --> 00:01:37,667 Many operate as heritage attractions that run 24 00:01:37,834 --> 00:01:38,868 out-of-date locomotives. 25 00:01:41,267 --> 00:01:42,767 They wind around the mountains. 26 00:01:44,100 --> 00:01:45,767 The result is slow travel. 27 00:01:47,100 --> 00:01:50,267 The 60-mile journey from Krakow to Nowy Sacz 28 00:01:50,434 --> 00:01:52,033 can take almost three hours. 29 00:01:54,501 --> 00:01:57,801 Reaching the mountain resort of Zakopane takes just as long. 30 00:02:01,367 --> 00:02:04,267 Now, engineers are building a brand-new railway 31 00:02:04,434 --> 00:02:05,534 through these mountains. 32 00:02:06,767 --> 00:02:10,400 When complete, Podleze-Piekielko Railway Line 33 00:02:10,567 --> 00:02:14,100 will cut journey times to around one hour to Nowy Sacz 34 00:02:14,267 --> 00:02:16,200 and 90 minutes to Zakopane, 35 00:02:17,767 --> 00:02:21,267 opening the region to faster travel, daily commuting, 36 00:02:21,434 --> 00:02:22,934 and millions of tourists. 37 00:02:25,367 --> 00:02:27,801 To complete the route, engineers must use 38 00:02:27,968 --> 00:02:31,968 giant machines to build over 80 supersized embankments to 39 00:02:32,133 --> 00:02:33,567 hold back the unstable ground. 40 00:02:35,868 --> 00:02:40,267 Workers must lay over 35 miles of new track 41 00:02:40,434 --> 00:02:44,667 and build 142 switches with millimeter precision to guide 42 00:02:44,834 --> 00:02:46,000 trains along the route. 43 00:02:47,267 --> 00:02:50,267 Huge boring machines will punch 20 tunnels beneath 44 00:02:50,434 --> 00:02:53,701 the mountains, one of which will be the longest in Poland. 45 00:02:55,701 --> 00:02:57,000 To keep on schedule, 46 00:02:57,167 --> 00:02:59,367 they will build a one-of-a-kind factory to make 47 00:02:59,534 --> 00:03:02,167 the thousands of segments that line each tunnel. 48 00:03:05,667 --> 00:03:07,667 When complete, the line will connect 49 00:03:07,834 --> 00:03:09,467 the cities of Southern Poland 50 00:03:09,634 --> 00:03:12,100 and open the region to faster travel, 51 00:03:12,267 --> 00:03:13,901 easier daily journeys 52 00:03:14,067 --> 00:03:15,968 and a huge increase in visitors. 53 00:03:21,000 --> 00:03:24,100 Construction of the railway is projected to take seven years. 54 00:03:26,467 --> 00:03:28,467 Meeting this deadline won't be easy. 55 00:03:30,267 --> 00:03:33,767 The route must cross multiple rivers, valleys, and roads. 56 00:03:35,400 --> 00:03:38,767 And long sections must be as straight as possible to 57 00:03:38,934 --> 00:03:40,467 accommodate trains traveling up 58 00:03:40,634 --> 00:03:43,067 to speeds of nearly 100 miles an hour. 59 00:03:44,868 --> 00:03:47,000 [Lukasz speaking Polish] 60 00:03:58,100 --> 00:04:00,801 The first challenge for the engineers lies beneath 61 00:04:00,968 --> 00:04:02,667 the surface in the geology of 62 00:04:02,834 --> 00:04:04,367 the Carpathian Mountains. 63 00:04:06,267 --> 00:04:09,100 This region is built from layers of rock known as 64 00:04:09,267 --> 00:04:13,200 flysch, alternating bands of hard stone and weak clay. 65 00:04:14,667 --> 00:04:17,267 When water seeps into these layers, they can begin to 66 00:04:17,434 --> 00:04:20,767 slide, making the slopes inherently unstable. 67 00:04:23,000 --> 00:04:25,801 [speaking Polish] 68 00:04:34,367 --> 00:04:36,467 Landslides are frequent in this region. 69 00:04:38,267 --> 00:04:39,501 They destroy property. 70 00:04:39,667 --> 00:04:41,167 [cracking, rumbling] 71 00:04:43,367 --> 00:04:44,367 Crush roads. 72 00:04:45,567 --> 00:04:47,400 They can also cut off railways. 73 00:04:51,567 --> 00:04:54,667 Now, engineers must carve a new railway corridor 74 00:04:54,834 --> 00:04:56,467 through steep mountain slopes 75 00:04:56,634 --> 00:04:58,400 in the town of Limanowa. 76 00:05:00,267 --> 00:05:02,701 Limanowa is densely built up, 77 00:05:02,868 --> 00:05:05,667 with homes and roads running close to the construction site. 78 00:05:07,868 --> 00:05:09,901 If engineers cut into these hillsides 79 00:05:10,067 --> 00:05:12,467 without reinforcement, the consequences 80 00:05:12,634 --> 00:05:14,267 could be catastrophic. 81 00:05:14,434 --> 00:05:16,901 [Rafal speaking Polish] 82 00:05:33,901 --> 00:05:37,367 Rafal Sitek is responsible for making sure the ground 83 00:05:37,534 --> 00:05:41,501 around the railway is rock solid and finding a way to hold 84 00:05:41,667 --> 00:05:43,234 these hillsides in place. 85 00:05:45,667 --> 00:05:49,100 On the gentler slopes, they use special ground nails 86 00:05:49,267 --> 00:05:50,267 to stabilize the earth. 87 00:05:54,000 --> 00:05:56,868 A drilling rig positions itself against the cut slope. 88 00:05:59,267 --> 00:06:03,267 It bores deep holes at precise angles into the ground. 89 00:06:05,701 --> 00:06:08,467 Workers feed a steel bar into each hole. 90 00:06:10,367 --> 00:06:13,501 Then they pump in grout to fill the spaces 91 00:06:13,667 --> 00:06:15,100 and lock the steel into place. 92 00:06:18,467 --> 00:06:21,767 Each nail reinforces the soil from within, 93 00:06:21,934 --> 00:06:23,167 increasing its strength 94 00:06:23,334 --> 00:06:24,968 and helping prevent it from slipping. 95 00:06:27,267 --> 00:06:30,200 On this site alone, workers install thousands of 96 00:06:30,367 --> 00:06:33,868 these anchors to create over 18 miles of reinforcement. 97 00:06:37,567 --> 00:06:39,100 Yet some sections of the railway 98 00:06:39,267 --> 00:06:40,367 are far more demanding. 99 00:06:42,467 --> 00:06:45,467 In the center of Limanowa, the line cuts deep 100 00:06:45,634 --> 00:06:46,701 into the slope. 101 00:06:48,400 --> 00:06:49,567 The loads are greater, 102 00:06:51,100 --> 00:06:53,567 and the excavation runs close to homes, 103 00:06:53,734 --> 00:06:55,467 roads, and the railway itself. 104 00:06:57,901 --> 00:07:01,100 Here, engineers need to take a different approach to 105 00:07:01,267 --> 00:07:02,267 stabilize the ground. 106 00:07:10,601 --> 00:07:14,167 A supersized rig drills a 35-inch wide hole 107 00:07:14,334 --> 00:07:16,400 up to 65 feet into the ground. 108 00:07:18,267 --> 00:07:21,267 It then fills the hole with concrete as it lifts up. 109 00:07:23,667 --> 00:07:25,868 Engineers drill a series of these holes 110 00:07:26,033 --> 00:07:27,501 with 50-inch gaps in between. 111 00:07:31,067 --> 00:07:34,000 Next, they drill secondary piles in these gaps. 112 00:07:37,400 --> 00:07:39,501 Before the concrete begins to harden, 113 00:07:39,667 --> 00:07:42,267 they insert reinforcement baskets into the shafts. 114 00:07:45,567 --> 00:07:48,467 The result is a solid underground wall 115 00:07:48,634 --> 00:07:50,801 that can hold back thousands of tons of earth. 116 00:07:58,467 --> 00:08:02,300 To build these walls, Rafal's team must drill piles 117 00:08:02,467 --> 00:08:04,501 deep into the unpredictable ground here. 118 00:08:06,968 --> 00:08:09,267 So the engineers bring in a powerful machine, 119 00:08:11,601 --> 00:08:14,300 standing nearly 100 feet tall, 120 00:08:16,767 --> 00:08:20,067 a beast that can drill deep into the toughest ground. 121 00:08:26,567 --> 00:08:29,467 Engineers start with drilling the primary piles. 122 00:08:31,868 --> 00:08:35,200 A steel casing rotates into the ground. 123 00:08:35,367 --> 00:08:39,501 Inside it, an auger spins in the opposite direction to cut 124 00:08:39,667 --> 00:08:42,501 into the soil and bring the material up to the surface. 125 00:08:48,167 --> 00:08:51,868 The deepest piles reach 65 feet into the ground, 126 00:08:52,033 --> 00:08:54,167 deeper than a six-story building. 127 00:08:56,601 --> 00:08:59,300 Once the hole reaches the required depth, 128 00:08:59,467 --> 00:09:01,267 workers withdraw the auger 129 00:09:01,434 --> 00:09:03,834 and pump concrete into the hole. 130 00:09:06,267 --> 00:09:08,868 The casing slowly lifts out of the hole 131 00:09:09,033 --> 00:09:11,100 as the concrete rises to fill the shaft. 132 00:09:13,300 --> 00:09:16,400 The machine then moves on, and the process begins again. 133 00:09:21,868 --> 00:09:24,167 Once the primary piles are dry, 134 00:09:24,334 --> 00:09:26,667 the team drills the secondary piles in between. 135 00:09:28,901 --> 00:09:33,167 The auger pumps concrete into the holes, and workers sink 136 00:09:33,334 --> 00:09:36,367 cylindrical reinforcement baskets made from steel 137 00:09:36,534 --> 00:09:37,601 into each one. 138 00:09:41,901 --> 00:09:45,367 These baskets run the full depth of the pile and make them 139 00:09:45,534 --> 00:09:47,567 strong enough to hold back the hillside. 140 00:09:52,901 --> 00:09:56,567 The team then removes thousands of tons of earth to reveal 141 00:09:56,734 --> 00:09:59,467 a megaterrace that eliminates the threat of landslides, 142 00:10:00,801 --> 00:10:02,467 to safeguard the railway 143 00:10:02,634 --> 00:10:04,467 and protect the passengers that will use it. 144 00:10:08,400 --> 00:10:11,400 Now that the ground is stable enough to build on, 145 00:10:11,567 --> 00:10:15,267 next, engineers must begin building the new railway. 146 00:10:25,367 --> 00:10:28,067 Engineers in Poland are building the ambitious 147 00:10:28,234 --> 00:10:31,300 new Podleze-Piekielko Railway Line 148 00:10:31,467 --> 00:10:34,267 that will slash journey times to the south of the country. 149 00:10:35,767 --> 00:10:38,901 The designers of the railway plan to build 22 stations 150 00:10:39,067 --> 00:10:40,267 and stops along the route. 151 00:10:42,100 --> 00:10:44,367 One of them is here in Limanowa. 152 00:10:48,567 --> 00:10:52,167 The station needs switches, precision track systems that 153 00:10:52,334 --> 00:10:54,400 guide trains from one track to another. 154 00:11:02,167 --> 00:11:04,767 Each switch is made from interlocking rails 155 00:11:04,934 --> 00:11:07,467 and moving blades that are engineered 156 00:11:07,634 --> 00:11:09,000 to millimeter precision. 157 00:11:10,567 --> 00:11:12,667 Get it wrong and the train could derail. 158 00:11:18,467 --> 00:11:21,200 Many switches for modern railways are made in factories 159 00:11:22,667 --> 00:11:24,667 and delivered pre-assembled to site. 160 00:11:28,367 --> 00:11:32,400 Here, they must bring in 100-foot lengths of track 161 00:11:32,567 --> 00:11:35,400 and assemble the switch piece by piece on site. 162 00:11:39,367 --> 00:11:43,000 First, workers lay down two steel assembly rails. 163 00:11:44,367 --> 00:11:48,100 Next, they lay the numbered concrete switch bearers on top 164 00:11:48,267 --> 00:11:49,367 in a precise sequence. 165 00:11:50,567 --> 00:11:53,501 Above these, they position the steel rails 166 00:11:53,667 --> 00:11:56,667 so they align with pre-cast fixing points in the bearers. 167 00:11:59,067 --> 00:12:02,300 They fix the rails and switch elements in place. 168 00:12:02,467 --> 00:12:04,601 Fastening systems lock everything together. 169 00:12:08,267 --> 00:12:12,067 After inspection, workers can remove the assembly rails, 170 00:12:12,234 --> 00:12:14,901 and the switch will rest exactly where it was built. 171 00:12:23,601 --> 00:12:27,000 This week, engineers must build a complete railway switch 172 00:12:27,167 --> 00:12:28,267 for Limanowa Station. 173 00:12:33,167 --> 00:12:37,501 Overseeing this task is railway engineer Marcin Iwanow. 174 00:12:44,267 --> 00:12:46,200 [speaking Polish] 175 00:12:55,000 --> 00:13:00,167 First, Marcin's team lays out 124 concrete slabs 176 00:13:00,334 --> 00:13:01,467 called switch bearers. 177 00:13:02,567 --> 00:13:04,467 Each one is numbered and placed in 178 00:13:04,634 --> 00:13:06,467 a precise sequence to form 179 00:13:06,634 --> 00:13:08,400 the exact geometry of the switch. 180 00:13:09,801 --> 00:13:12,501 The switch bearers hold the steel rails in place. 181 00:13:13,601 --> 00:13:16,400 The team must position them precisely. 182 00:13:16,567 --> 00:13:19,133 Otherwise, the rails won't fit. 183 00:13:21,601 --> 00:13:23,000 Now for the heavy lift. 184 00:13:24,467 --> 00:13:26,901 The switch has two arms. 185 00:13:27,067 --> 00:13:28,868 These are the tapered steel rails that 186 00:13:29,033 --> 00:13:31,367 move back and forth to switch the track. 187 00:13:33,667 --> 00:13:35,868 Each one weighs about three tons. 188 00:13:37,100 --> 00:13:38,868 The team must use a crane to place 189 00:13:39,033 --> 00:13:40,767 both precisely into position. 190 00:13:43,100 --> 00:13:45,901 But the unstable ground of Carpathian flysch 191 00:13:46,067 --> 00:13:47,100 adds another challenge. 192 00:13:48,667 --> 00:13:50,767 [speaking Polish] 193 00:13:56,067 --> 00:13:57,868 The crane moves into position. 194 00:14:20,767 --> 00:14:22,200 The ground gives way. 195 00:14:22,367 --> 00:14:23,901 And one side of the crane sinks. 196 00:14:28,200 --> 00:14:30,100 If the crane isn't level, 197 00:14:30,267 --> 00:14:32,567 the entire machine could tip over during the lift. 198 00:14:37,267 --> 00:14:39,634 The engineers must find a solution. 199 00:14:42,100 --> 00:14:46,200 An excavator cuts into the soft ground to create a stable base. 200 00:14:48,367 --> 00:14:49,901 Workers lay old sleepers 201 00:14:50,067 --> 00:14:51,767 beneath the crane's support leg 202 00:14:51,934 --> 00:14:53,400 to spread the machine's load. 203 00:14:54,667 --> 00:14:56,367 [Marcin speaking Polish] 204 00:14:58,701 --> 00:15:01,567 The crane extends its outriggers and workers 205 00:15:01,734 --> 00:15:04,701 attach them to metal feet placed on top of the sleepers. 206 00:15:08,000 --> 00:15:10,000 Slowly, the machine levels out. 207 00:15:17,000 --> 00:15:18,767 The crane is ready to make the lift. 208 00:15:25,100 --> 00:15:27,167 It lowers the first arm into place. 209 00:15:33,267 --> 00:15:34,300 Followed by the second. 210 00:15:38,601 --> 00:15:42,100 Final alignment can only be done by hand, 211 00:15:42,267 --> 00:15:43,667 but it is not an easy task. 212 00:15:47,300 --> 00:15:49,767 [speaking Polish] 213 00:15:59,300 --> 00:16:02,467 Workers use bars and levers to make small controlled 214 00:16:02,634 --> 00:16:04,667 adjustments until everything fits. 215 00:16:09,901 --> 00:16:13,067 They guide each element onto precast fixing points. 216 00:16:15,501 --> 00:16:18,000 These transfer the load of passing trains into 217 00:16:18,167 --> 00:16:21,367 the concrete foundation to ensure the switch's stability. 218 00:16:25,467 --> 00:16:28,701 Workers move along the switch to tighten each connection. 219 00:16:32,267 --> 00:16:35,267 It takes the team 20 hours to complete the first of 220 00:16:35,434 --> 00:16:37,133 nine switches at the station. 221 00:16:39,567 --> 00:16:43,067 Once finished, these will form a precision system to 222 00:16:43,234 --> 00:16:46,100 guide trains safely from one track to another. 223 00:16:48,567 --> 00:16:50,300 But for their next challenge, 224 00:16:50,467 --> 00:16:53,267 the team will be forced to go underground. 225 00:16:59,601 --> 00:17:01,767 In Poland, engineers are building 226 00:17:01,934 --> 00:17:05,400 the new Podleze-Piekielko Railway Line 227 00:17:05,567 --> 00:17:08,667 to access the spectacular Carpathian Mountains 228 00:17:08,834 --> 00:17:10,267 in the south of the country. 229 00:17:11,767 --> 00:17:13,868 Slashing journey times is a priority for 230 00:17:14,033 --> 00:17:15,000 the railway's designers. 231 00:17:19,467 --> 00:17:21,767 [speaking Polish] 232 00:17:32,000 --> 00:17:35,667 The undulating topography of the Carpathian foothills makes 233 00:17:35,834 --> 00:17:38,501 a straight route above ground almost impossible. 234 00:17:39,667 --> 00:17:42,400 So engineers are punching 13 tunnels, 235 00:17:42,567 --> 00:17:45,300 totaling nearly 20 miles through these mountains. 236 00:17:48,767 --> 00:17:51,968 The engineers digging the tunnel at Mecina must 237 00:17:52,133 --> 00:17:55,100 bring in two special tunneling machines to get the job done. 238 00:18:02,801 --> 00:18:06,367 The two mega tunnel boring machines arrive in pieces at 239 00:18:06,534 --> 00:18:09,400 the ports of Gdansk and Gdynia in northern Poland. 240 00:18:12,901 --> 00:18:15,968 The construction site is 435 miles south. 241 00:18:17,901 --> 00:18:19,767 It's mid-December. 242 00:18:19,934 --> 00:18:22,200 Heavy transportation will soon shut down for 243 00:18:22,367 --> 00:18:23,734 the Christmas holiday. 244 00:18:25,100 --> 00:18:28,667 Engineers are in a race against time to move thousands of tons 245 00:18:28,834 --> 00:18:30,367 of machinery across the country... 246 00:18:31,667 --> 00:18:33,167 before the window closes. 247 00:18:35,567 --> 00:18:37,100 Their first challenge is to 248 00:18:37,267 --> 00:18:38,767 unload everything from the ship, 249 00:18:39,868 --> 00:18:42,000 in winter and against the clock. 250 00:18:46,100 --> 00:18:49,868 Jaroslaw Joniec and Maciej Stec are in charge of 251 00:18:50,033 --> 00:18:51,167 the mammoth operation. 252 00:18:53,067 --> 00:18:55,367 [Jaroslaw speaking Polish] 253 00:19:14,100 --> 00:19:15,701 Deep inside the hold, 254 00:19:15,868 --> 00:19:17,567 the components sit wrapped in tarps. 255 00:19:23,167 --> 00:19:26,167 Workers climb down to rig the lifting straps. 256 00:19:30,067 --> 00:19:31,801 [Maciej speaking Polish] 257 00:19:38,100 --> 00:19:40,367 Then, the cranes take the load. 258 00:19:44,501 --> 00:19:47,267 One by one, the components emerge. 259 00:19:47,434 --> 00:19:50,300 The smaller parts go on to standard trucks, 260 00:19:50,467 --> 00:19:53,467 but the largest elements need specialized low loaders. 261 00:20:01,501 --> 00:20:05,367 The heaviest elements weigh over 110 tons, 262 00:20:05,534 --> 00:20:07,300 too heavy for a single crane. 263 00:20:09,767 --> 00:20:11,601 So for the most demanding lifts, 264 00:20:11,767 --> 00:20:13,400 two cranes work together. 265 00:20:22,000 --> 00:20:25,100 Finally, after three days of around-the-clock work... 266 00:20:33,100 --> 00:20:35,267 the last component touches the quayside. 267 00:20:44,267 --> 00:20:45,467 And as night falls, 268 00:20:47,467 --> 00:20:50,667 the convoy sets off through the streets of Gdynia, 269 00:20:50,834 --> 00:20:54,400 and it begins its 435-mile journey south. 270 00:21:00,100 --> 00:21:02,467 But not every road can take the weight, 271 00:21:02,634 --> 00:21:04,667 and not every bridge is strong enough. 272 00:21:06,801 --> 00:21:10,133 So heavy loads move slowly on pre-approved routes. 273 00:21:12,567 --> 00:21:15,667 The final stretch along steep, narrow mountain roads 274 00:21:15,834 --> 00:21:17,167 is the most challenging. 275 00:21:19,667 --> 00:21:22,467 [speaking Polish] 276 00:21:29,501 --> 00:21:31,367 [Maciej speaking Polish] 277 00:21:40,067 --> 00:21:42,100 Drivers can't rely on visibility alone. 278 00:21:44,100 --> 00:21:47,567 Pilots walk ahead, guiding every move by radio. 279 00:21:50,000 --> 00:21:53,667 Finally, the convoy reaches the construction site. 280 00:21:56,100 --> 00:21:58,067 The engineer's next challenge is to assemble 281 00:21:58,234 --> 00:22:01,300 the 172 components, 282 00:22:01,467 --> 00:22:04,400 weighing 3,400 tons, 283 00:22:04,567 --> 00:22:06,501 into a pair of tunneling machines. 284 00:22:08,000 --> 00:22:09,701 [Maciej speaking Polish] 285 00:22:17,501 --> 00:22:19,667 They named the larger machine Jadwiga, 286 00:22:20,801 --> 00:22:24,701 and the smaller one Kinga, honoring two of Poland's most 287 00:22:24,868 --> 00:22:26,801 revered medieval royal saints. 288 00:22:32,000 --> 00:22:34,267 Space in front of the rock face is tight. 289 00:22:37,667 --> 00:22:40,667 The team must build the 330-foot-long tunnel 290 00:22:40,834 --> 00:22:42,767 drilling machines within a space 291 00:22:42,934 --> 00:22:44,868 that measures nearly 400 feet. 292 00:22:48,868 --> 00:22:51,400 After seven weeks, Kinga is ready. 293 00:22:55,367 --> 00:22:57,467 The crew fires up her cutterhead, 294 00:22:58,767 --> 00:23:01,567 and the machine prepares to tear into the rock. 295 00:23:11,801 --> 00:23:16,467 To build the Podleze-Piekielko Railway Line, engineers must 296 00:23:16,634 --> 00:23:19,467 drive tunnels deep beneath the Carpathian Mountains. 297 00:23:21,501 --> 00:23:23,567 [speaking Polish] 298 00:23:36,701 --> 00:23:39,100 The first two tunnels were run beneath the village 299 00:23:39,267 --> 00:23:40,467 of Pisarzowa. 300 00:23:42,567 --> 00:23:44,367 One will carry the railway. 301 00:23:44,534 --> 00:23:46,467 The other will serve as an excavation tunnel. 302 00:23:51,167 --> 00:23:54,000 They will run for nearly two and a half miles, 303 00:23:54,167 --> 00:23:57,067 the longest railway tunnels in Poland. 304 00:23:59,501 --> 00:24:02,567 But the ground here is made from highly unstable layers of 305 00:24:02,734 --> 00:24:04,934 rock and clay that can shift. 306 00:24:07,367 --> 00:24:09,767 There is a danger that a collapse could trap 307 00:24:09,934 --> 00:24:12,167 the tunneling machine beneath the surface 308 00:24:12,334 --> 00:24:14,367 and endanger its crew. 309 00:24:14,534 --> 00:24:17,267 To prevent this, Jadwiga and Kinga 310 00:24:17,434 --> 00:24:19,601 are a special type of tunnel boring machine 311 00:24:19,767 --> 00:24:24,501 called an Earth Pressure Balance, or EPB-TBM. 312 00:24:26,100 --> 00:24:28,167 This is how it works. 313 00:24:28,334 --> 00:24:31,467 A rotating cutterhead breaks through the ground. 314 00:24:31,634 --> 00:24:34,868 The excavated material enters a sealed chamber behind it. 315 00:24:36,167 --> 00:24:40,000 Here, it mixes with water, air, and foaming agent to 316 00:24:40,167 --> 00:24:42,467 create a sludge that is held 317 00:24:42,634 --> 00:24:44,400 under pressure inside the chamber. 318 00:24:46,100 --> 00:24:49,467 It pushes back against the rock to keep the tunnel stable 319 00:24:49,634 --> 00:24:51,701 and prevent collapse. 320 00:24:51,868 --> 00:24:54,567 A screw conveyor controls the amount of material that 321 00:24:54,734 --> 00:24:57,267 leaves the chamber to maintain the pressure balance. 322 00:24:58,701 --> 00:25:02,467 Next, the spoil is transferred onto a conveyor belt 323 00:25:02,634 --> 00:25:04,267 and carried out of the tunnel. 324 00:25:05,701 --> 00:25:08,267 As the TBM advances, it installs 325 00:25:08,434 --> 00:25:10,567 precast concrete segments behind it. 326 00:25:11,767 --> 00:25:14,267 Hydraulic jacks push on them to move forward 327 00:25:14,434 --> 00:25:17,334 and help form a sealed tunnel lining. 328 00:25:19,767 --> 00:25:23,467 Two TBMs build the railway tunnel and excavation tunnel 329 00:25:23,634 --> 00:25:25,000 at the same time. 330 00:25:29,000 --> 00:25:31,267 But cutting through the Carpathian flysch 331 00:25:31,434 --> 00:25:33,434 is no simple task. 332 00:25:35,868 --> 00:25:39,267 It's the responsibility of TBM manager Veysel Dalmis 333 00:25:39,434 --> 00:25:41,167 to keep the machines on track. 334 00:25:51,000 --> 00:25:53,567 And the tunneling machine's crew faces an even more 335 00:25:53,734 --> 00:25:55,367 dangerous invisible threat. 336 00:25:57,701 --> 00:26:01,200 Pockets of methane gas can be trapped inside the rock. 337 00:26:02,701 --> 00:26:04,801 Methane is deadly for humans, 338 00:26:04,968 --> 00:26:06,667 and in a high enough concentration, 339 00:26:06,834 --> 00:26:08,167 it can become explosive. 340 00:26:09,868 --> 00:26:13,667 Even a small spark from metal contact from machinery 341 00:26:13,834 --> 00:26:15,467 could ignite it. 342 00:26:17,901 --> 00:26:20,467 An explosion underground would be catastrophic for 343 00:26:20,634 --> 00:26:21,968 both the tunnel 344 00:26:22,133 --> 00:26:24,567 and the village above. 345 00:26:27,000 --> 00:26:31,200 So the EPB-TBM has sensors throughout the machine that 346 00:26:31,367 --> 00:26:33,667 constantly measure the amount of methane in the tunnel. 347 00:26:54,000 --> 00:26:57,367 The engineers' next challenge is to stop the immense pressure 348 00:26:57,534 --> 00:27:00,868 of the ground from crushing the newly excavated tunnel. 349 00:27:03,300 --> 00:27:07,000 The TBM's solution is to line the interior of the tunnel 350 00:27:07,167 --> 00:27:09,067 with precast concrete segments. 351 00:27:13,567 --> 00:27:16,601 As the cutterhead advances, a motorized arm 352 00:27:16,767 --> 00:27:18,100 swings into action behind it. 353 00:27:22,367 --> 00:27:25,868 It picks up each segment using a powerful vacuum grip. 354 00:27:30,601 --> 00:27:31,868 Rotates it into position. 355 00:27:37,467 --> 00:27:40,267 And locks it into place against the tunnel wall. 356 00:27:46,467 --> 00:27:49,267 Seven segments form a complete ring, 357 00:27:52,767 --> 00:27:54,667 each one bolted to the next. 358 00:28:00,167 --> 00:28:02,100 Rubber seals between them help 359 00:28:02,267 --> 00:28:03,868 keep groundwater out of the tunnel. 360 00:28:09,467 --> 00:28:11,567 Each ring is strong enough to resist 361 00:28:11,734 --> 00:28:13,100 the crush of the earth above 362 00:28:14,701 --> 00:28:17,567 and maintain the tunnel's 35-foot diameter. 363 00:28:21,501 --> 00:28:24,868 But digging the tunnel is only half the job, 364 00:28:25,033 --> 00:28:28,367 because everything the machine cuts must go somewhere. 365 00:28:31,767 --> 00:28:33,467 A continuous conveyor belt 366 00:28:33,634 --> 00:28:36,567 carries tons of earth and rock out of the tunnel. 367 00:28:39,000 --> 00:28:41,601 The TBM is constantly moving forward. 368 00:28:43,400 --> 00:28:45,567 As it advances, the conveyor system 369 00:28:45,734 --> 00:28:46,968 must grow with it. 370 00:28:51,267 --> 00:28:53,968 The machine stops at regular intervals for maintenance. 371 00:28:56,200 --> 00:28:59,868 And in this limited window, crews must bond a new length of 372 00:29:00,100 --> 00:29:02,000 belt to make the conveyor longer. 373 00:29:03,767 --> 00:29:07,267 To extend the belt, they use vulcanization, 374 00:29:07,434 --> 00:29:10,868 a process that fuses the belt together using heat, 375 00:29:11,033 --> 00:29:13,634 pressure, and layered bonding materials. 376 00:29:16,100 --> 00:29:18,868 After several hours, the belt becomes 377 00:29:19,033 --> 00:29:20,400 one continuous length. 378 00:29:29,400 --> 00:29:31,467 With the new section installed, 379 00:29:31,634 --> 00:29:34,300 the team now needs to keep the mountain above 380 00:29:34,467 --> 00:29:36,300 from caving in on them. 381 00:29:48,200 --> 00:29:51,300 Engineers in Poland are punching two tunnels through 382 00:29:51,467 --> 00:29:55,367 challenging geology as part of a brand new railway line in 383 00:29:55,534 --> 00:29:56,467 the south of the country. 384 00:30:01,067 --> 00:30:03,901 As it advances, the tunneling machine builds 385 00:30:04,067 --> 00:30:07,467 behind it a concrete lining made from precast segments. 386 00:30:10,701 --> 00:30:12,667 [speaking Polish] 387 00:30:25,601 --> 00:30:29,000 These rings hold back the weight of the ground above. 388 00:30:31,467 --> 00:30:34,467 The pair of tunnels beneath Pisarzowa require 389 00:30:34,634 --> 00:30:37,367 more than 28,700 segments. 390 00:30:41,667 --> 00:30:44,467 The tunnel-digging machine needs a steady supply of these 391 00:30:44,634 --> 00:30:46,200 to keep working around the clock. 392 00:30:50,801 --> 00:30:53,767 To solve this problem, engineers build a dedicated 393 00:30:53,934 --> 00:30:55,667 segment factory beside the tunnel. 394 00:30:57,467 --> 00:31:00,100 At its heart is a carousel production line. 395 00:31:01,767 --> 00:31:05,367 First, workers clean a segment mold and spray it 396 00:31:05,534 --> 00:31:09,000 with a release agent to stop the concrete from sticking. 397 00:31:09,167 --> 00:31:11,667 Next, they fit a ceiling gasket 398 00:31:11,834 --> 00:31:14,467 and lower a steel reinforcement cage inside. 399 00:31:16,367 --> 00:31:19,267 Then, they close the mold and fill it with concrete. 400 00:31:20,767 --> 00:31:24,000 Vibrators shake the mix into every corner of the form. 401 00:31:25,267 --> 00:31:27,968 The mold then moves into a heated curing chamber. 402 00:31:29,801 --> 00:31:32,868 Several hours later, workers open the mold 403 00:31:33,033 --> 00:31:34,601 and lift out the finished segment. 404 00:31:36,467 --> 00:31:39,868 Soon after, crews transport it underground 405 00:31:40,033 --> 00:31:43,300 for the tunnel-digging machine to install inside the tunnel. 406 00:31:48,567 --> 00:31:50,200 The molds are designed to produce 407 00:31:50,367 --> 00:31:51,801 millimeter-accurate segments. 408 00:31:55,267 --> 00:31:58,000 Workers clean each mold and then spray it with 409 00:31:58,167 --> 00:31:59,868 an anti-adhesive coating... 410 00:32:02,400 --> 00:32:04,000 and fit a sealing gasket 411 00:32:04,167 --> 00:32:06,467 to help waterproof the finished tunnel. 412 00:32:08,901 --> 00:32:12,267 Then, they lower a steel reinforcement cage inside. 413 00:32:16,167 --> 00:32:19,000 By the end of production, the factory will use around 414 00:32:19,167 --> 00:32:22,968 5,200 tons of reinforcing steel to build the cages 415 00:32:23,133 --> 00:32:24,067 for every segment. 416 00:32:28,467 --> 00:32:32,200 Once workers close the mold, they pour in the concrete. 417 00:32:34,667 --> 00:32:38,367 Mixer trucks deliver each batch from a local supplier. 418 00:32:40,801 --> 00:32:42,767 Engineers use a high-strength mix 419 00:32:42,934 --> 00:32:45,267 designed for extreme underground conditions. 420 00:32:49,601 --> 00:32:53,067 Steel fibers reinforce the concrete and help it 421 00:32:53,234 --> 00:32:56,701 withstand temperatures of over 2,100 degrees Fahrenheit. 422 00:33:01,567 --> 00:33:04,868 Vibrators shake the mix into every corner of the form. 423 00:33:06,901 --> 00:33:09,467 Then, crews remove the excess concrete 424 00:33:09,634 --> 00:33:11,133 and smooth the outer surface. 425 00:33:13,567 --> 00:33:16,701 This closes the pores in the concrete and improves 426 00:33:16,868 --> 00:33:18,734 its resistance to water. 427 00:33:21,167 --> 00:33:24,267 Now, workers move the segment into a curing chamber. 428 00:33:28,400 --> 00:33:31,467 Here, engineers control the heat and humidity. 429 00:33:35,267 --> 00:33:37,968 Temperatures reach 130 degrees Fahrenheit, 430 00:33:38,968 --> 00:33:41,167 and humidity approaches 100%. 431 00:33:42,767 --> 00:33:44,601 These conditions help the concrete 432 00:33:44,767 --> 00:33:46,100 harden and gain strength. 433 00:33:51,267 --> 00:33:54,000 After roughly eight hours, the segment is ready. 434 00:34:01,000 --> 00:34:03,868 These rings must withstand enormous pressure from 435 00:34:04,033 --> 00:34:05,267 the weight of the mountain above. 436 00:34:09,167 --> 00:34:12,901 If the concrete is too weak, the lining could fail, 437 00:34:13,067 --> 00:34:16,367 so engineers must test every completed batch before 438 00:34:16,534 --> 00:34:18,000 they're installed inside the tunnel. 439 00:34:22,567 --> 00:34:25,501 Workers take samples from the concrete mix and pour them 440 00:34:25,667 --> 00:34:26,667 into small cubes. 441 00:34:35,100 --> 00:34:38,000 After curing, engineers place the cubes 442 00:34:38,167 --> 00:34:40,000 inside a compression testing machine. 443 00:34:41,968 --> 00:34:44,200 The machine increases the pressure until 444 00:34:44,367 --> 00:34:45,267 the concrete fails. 445 00:34:56,601 --> 00:34:59,000 The result shows whether the mix is strong enough 446 00:34:59,167 --> 00:35:00,400 for the tunnel lining. 447 00:35:05,968 --> 00:35:09,400 If the segment passes inspection, a scissor grab 448 00:35:09,567 --> 00:35:10,634 lifts it from the mold... 449 00:35:12,801 --> 00:35:15,000 and rotates it into its storage position. 450 00:35:17,267 --> 00:35:20,901 The concrete continues to harden for three more days in 451 00:35:21,067 --> 00:35:23,000 covered storage beside the factory. 452 00:35:24,100 --> 00:35:26,767 After that, workers move the segment 453 00:35:26,934 --> 00:35:28,000 into the storage yard. 454 00:35:32,300 --> 00:35:35,367 This innovative factory supplies the TBM with 455 00:35:35,534 --> 00:35:38,868 a constant stream of super strong concrete segments 456 00:35:40,367 --> 00:35:43,701 to keep the tunneling machine advancing through the mountain 457 00:35:43,868 --> 00:35:45,501 24 hours a day. 458 00:35:46,667 --> 00:35:49,667 Now, engineers prepare for the final step 459 00:35:49,834 --> 00:35:52,400 of the tunnel-building -- the breakthrough. 460 00:36:00,167 --> 00:36:03,367 Engineers in Southern Poland are close to completing 461 00:36:03,534 --> 00:36:06,400 the country's longest railway tunnels. 462 00:36:08,868 --> 00:36:12,367 Today, they prepare the smaller tunnel-boring machine to cut 463 00:36:12,534 --> 00:36:14,000 through the final feet of rock, 464 00:36:15,200 --> 00:36:18,067 a critical stage known as the breakthrough. 465 00:36:31,567 --> 00:36:35,300 Worn cutting tools can stop the TBM from excavating safely. 466 00:36:39,100 --> 00:36:41,200 The tunnel face could collapse during breakthrough. 467 00:36:47,167 --> 00:36:50,667 Chief engineer Veysel uses a special train to travel 468 00:36:50,834 --> 00:36:53,567 the two and a half miles from the tunnel's entrance to 469 00:36:53,734 --> 00:36:55,267 the TBM at the other end. 470 00:36:57,567 --> 00:37:00,267 The buildup of methane inside the tunnel 471 00:37:00,434 --> 00:37:01,567 could still pose a risk. 472 00:37:05,968 --> 00:37:08,167 So Veysel carries a self-rescuer, 473 00:37:09,300 --> 00:37:11,667 an emergency breathing device that gives him 474 00:37:11,834 --> 00:37:13,267 enough time to escape. 475 00:37:23,767 --> 00:37:26,467 Veysel arrives at the rear of the tunneling machine. 476 00:37:27,801 --> 00:37:31,434 Getting from here to the rock face is a journey in itself. 477 00:37:33,901 --> 00:37:37,567 The tunnel-digging machine is now nearly two and a half miles 478 00:37:37,734 --> 00:37:39,701 inside the mountain, 479 00:37:39,868 --> 00:37:42,100 the furthest it has ever been from the exit. 480 00:37:43,501 --> 00:37:46,167 If something goes wrong here, getting out is 481 00:37:46,334 --> 00:37:50,000 not straightforward, and a self-rescuer alone 482 00:37:50,167 --> 00:37:51,767 might not be enough. 483 00:37:51,934 --> 00:37:54,767 So designers equipped Kinga and Jadwiga 484 00:37:54,934 --> 00:37:56,868 with rescue chambers. 485 00:37:59,300 --> 00:38:03,100 They are airtight and fully self-contained with 486 00:38:03,267 --> 00:38:04,601 emergency power and provisions. 487 00:38:05,968 --> 00:38:09,567 Even if the machines come to a standstill, safety systems 488 00:38:09,734 --> 00:38:13,801 continuously pump in fresh air and regulate the temperature. 489 00:38:15,167 --> 00:38:17,701 The rescue chambers can keep workers alive for up to 490 00:38:17,868 --> 00:38:21,367 24 hours, long enough for help to reach them. 491 00:38:28,767 --> 00:38:30,300 Just behind the tunnel face, 492 00:38:30,467 --> 00:38:33,701 Veysel opens the maintenance hatch and climbs inside 493 00:38:33,868 --> 00:38:35,000 the cutterhead. 494 00:38:42,300 --> 00:38:45,267 He checks each cutting tool for wear and damage. 495 00:39:00,667 --> 00:39:03,567 Veysel signals to the operator to rotate the cutterhead. 496 00:39:19,200 --> 00:39:20,367 The machine is ready. 497 00:39:22,567 --> 00:39:24,267 Veysel exits the tunnel 498 00:39:24,434 --> 00:39:26,267 and goes to the place where engineers 499 00:39:26,434 --> 00:39:30,167 and officials have gathered to witness the breakthrough. 500 00:39:30,334 --> 00:39:32,968 From here, he coordinates the final push. 501 00:39:50,868 --> 00:39:55,601 There is one more obstacle in the way, a thick concrete wall 502 00:39:55,767 --> 00:39:57,467 reinforced with steel piles. 503 00:39:59,367 --> 00:40:02,467 The tunnel drilling machine must break through it cleanly. 504 00:40:03,868 --> 00:40:07,467 If the machine is misaligned, it could strike the circular 505 00:40:07,634 --> 00:40:09,767 mouth of the tunnel, which could collapse. 506 00:40:19,000 --> 00:40:22,367 At last, the cutterhead reaches the final barrier. 507 00:40:49,667 --> 00:40:51,367 The piles give way, 508 00:40:51,534 --> 00:40:53,467 and the tunnelling machine breaks through. 509 00:40:53,634 --> 00:40:55,868 [crowd cheering] 510 00:40:59,100 --> 00:41:01,267 [indistinct chatter] 511 00:41:10,567 --> 00:41:12,567 Now, the team can turn its attention to 512 00:41:12,734 --> 00:41:15,667 the 12 remaining tunnels along the route to complete 513 00:41:15,834 --> 00:41:17,067 the full railroad. 514 00:41:24,267 --> 00:41:28,267 To build Poland's extreme railway, this team of engineers 515 00:41:28,434 --> 00:41:30,000 stabilized dangerous slopes, 516 00:41:32,100 --> 00:41:36,601 transported giant machines 435 miles across the country, 517 00:41:38,300 --> 00:41:41,567 and drove record-breaking railway tunnels deep beneath 518 00:41:41,734 --> 00:41:42,868 the Carpathian Mountains. 519 00:41:47,968 --> 00:41:52,901 Now, Podleze-Piekielko Railway Line will open the region to 520 00:41:53,067 --> 00:41:55,901 quicker journeys, better connections, 521 00:41:56,067 --> 00:41:59,000 and a new era of rail travel through the Carpathians.