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.
Freight Cars in Service for railroads includes railroad-owned cars plus cars with a railroad's mark on January 1, which usually have a longer-term lease. The railroads also use equipment controlled by shippers and leasing companies, including railroad-owned TTX â one of the largest leasing companies. New freight cars cost between $70,000 and $260,000 depending on the type and features. The Class I railroad average for 2011 was $73,220.