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.
Cost Estimating Methodology for HSR on Shared Right-of-WayApril 18, 2011 factor of 1.035 (March 2010 was the most recent month for which PPI data was available at the time of this writing). Once the 2010 unit costs were derived, they were compared to current year industry cost estimates for railroad related construction; during this comparison, if a unit cost was found to be out of line with current trends, it was adjusted to better reflect current conditions in the market. The pay items and their associated unit costs