1. Scientists believe the mammoths only became visible because global warming had melted the permafrost - earth that normally remains frozen all year round.
2. Its discoverers aren't certain if it is rocky like Earth or if its a frozen ice ball with liquid water on the surface.
3. The research results have helped them map out a clear geological map of the activities of frozen earth.
4. But unlike their future peer in Tibet, these frozen earth railroads lie at higher altitudes which are very stable.
5. Zheng said work can only be done from May to September, while the rest of the time the earth is too frozen to dig.
6. About 550 km of the tracks run on frozen earth, the longest of any of the world's plateau railways.
7. They have pledged the railway will be able to run safely through the areas of frozen earth without any hiccups for 50 years.
8. Zhang said if the earth was more frozen and the temperature more stable, the train's speed can be pushed beyond 100 km.
9. The melting of the frozen earth beneath the surface is the cause of 80 percent of the damage to the road on the Plateau.
10. The earth is not as frozen as in winter, which won't make horse tumble.