Part 1 of Essay
In order to have easy mobility of persons and goods, it is necessary to have a sophisticated and widespread transportation system. This system is made up of five primary areas of transportation, which are: - Motor vehicles - Railroad transportation - Air transportation - Wat ....

Part 2 of Essay
.... operation and regulation of the different modes of transportation. Each mode is made up of primary subsystems. The subsystems of railroad transportation include freight trains and passenger trains. Freight trains are used to transport goods and materials between cities while passenger trains are used to transport people. Although freight trains are still used all across the nation, rail intercity freight has accounted for a decreasing share of the total ton mileage over the past 30 years. This is mostl ....