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.
Embankment costs, using imported material, range from $12 to $15 per cubic yard. Assuming a subcut excavation of thirty inches for the minimum paved roadway (CBJ Standard 102), the per lot cost for road excavation would range from $2,090 to $3,190. The cost per lot for imported road embankment would range from $3,190 to $3,960. These costs include all equipment, labor and materials.