The atoms that make up a molecule can be of the same element or different types. Diatomic molecules are a specific class of molecules that consist of two molecules of the same element. If the molecule is composed of atoms of at least two different elements, it is a chemical compound.
The cost of light rail construction varies widely, largely depending on the amount of tunneling and elevated structures required. A survey of North American light rail projects shows that costs of most LRT systems range from $15 million to over $100 million per mile.he cost of 17 miles (27 km) of highway improvements and 19 miles (31 km) of double-track light rail worked out to $19.3 million per highway lane-mile and $27.6 million per LRT track-mile. The project came in under budget and 22 months ahead of schedule.
âChina has accomplished a remarkable feat in building over 10,000 km of high speed railway network in a period of six to seven years at a unit cost that is lower than the cost of similar projects in other countries,â said Gerald Ollivier, a World Bank Senior Transport Specialist and co-author of the paper.hinaâs high speed rail with a maximum speed of 350 km/h has a typical infrastructure unit cost of about US$ 17-21m per km, with a high ratio of viaducts and tunnels, as compared with US$25-39 m per km in Europe and as high as US$ 56m per km currently estimated in California.