Once a railroad track is built, the ties are replaced sporatically based on wear and tear and weather damage; about every 10 yrs.
Wear and tear
Rail transport is a means of conveyance of passengers and goods, by way of wheeled vehicles running on rails. It is also commonly referred to as train transport. In contrast to road transport, where vehicles merely run on a prepared surface, rail vehicles are also directionally guided by the tracks on which they run. Track usually consists of steel rails installed on sleepers/ties and ballast, on which the rolling stock, usually fitted with metal wheels, moves. However, other variations are also possible, such as slab track where the rails are fastened to a concrete foundation resting on a prepared subsurface.
Rolling stock in railway transport systems generally has lower frictional resistance when compared with highway vehicles and the passenger and freight cars (carriages and wagons) can be coupled into longer trains. The operation is carried out by a railway company, providing transport between train stations or freight customer facilities. Power is provided by locomotives which either draw electrical power from a railway electrification system or produce their own power, usually by diesel engines. Most tracks are accompanied by a signalling system. Railways are a safe land transport system when compared to other forms of transport. Railway transport is capable of high levels of passenger and cargo utilization and energy efficiency, but is often less flexible and more capital-intensive than highway transport is, when lower traffic levels are considered.
Wear and tear is damage that naturally and inevitably occurs as a result of normal wear or aging. It is used in a legal context for such areas as warranty contracts from manufacturers, which usually stipulate that damage due to wear and tear will not be covered.
Wear and tear is a form of depreciation which is assumed to occur even when an item is used competently and with care and proper maintenance. For example, repeated impacts may cause stress to a hammer's head. In the normal use of a hammer for its designed task, this stress is impossible to prevent, and any attempt to eliminate it would make the hammer useless. At the same time, it is expected that the normal use of a hammer will not break it beyond repair until it has gone through a certain amount of use.
First Transcontinental Railroad
Dual gauge · Conversion (list) ·
Bogie exchange · Variable gauge
The track on a railway or railroad, also known as the permanent way, is the structure consisting of the rails, fasteners, railroad ties (sleepers, British English) and ballast (or slab track), plus the underlying subgrade. For clarity it is often referred to as railway track (British English and UIC terminology) or railroad track (predominantly in the United States).
The First Transcontinental Railroad (known originally as the "Pacific Railroad" and later as the "Overland Route") was a 1,907-mile (3,069 km) contiguous railroad line constructed between 1863 and 1869 across the western United States to connect the Pacific coast at San Francisco Bay with the existing Eastern U.S. rail network at Council Bluffs, Iowa, on the Missouri River. The rail line was built by three private companies: the original Western Pacific Railroad Company between Oakland and Sacramento, California (132 miles (212 km)), the Central Pacific Railroad Company of California eastward from Sacramento to Promontory Summit, Utah Territory (U.T.) (690 miles), and the Union Pacific Railroad Company westward to Promontory Summit from the road's statutory Eastern terminus at Council Bluffs on the eastern shore of the Missouri River opposite Omaha, Nebraska (1,085 miles).
Opened for through traffic on May 10, 1869, with the driving of the "Last Spike" with a silver hammer at Promontory Summit, the road established a mechanized transcontinental transportation network that revolutionized the settlement and economy of the American West by bringing these western states and territories firmly and profitably into the "Union" and making goods and transportation much quicker, cheaper and much more flexible from coast to coast.
A disaster is a natural or man-made (or technological) hazard resulting in an event of substantial extent causing significant physical damage or destruction, loss of life, or drastic change to the environment. A disaster can be ostensively defined as any tragic event stemming from events such as earthquakes, floods, catastrophic accidents, fires, or explosions. It is a phenomenon that can cause damage to life and property and destroy the economic, social and cultural life of people.
In contemporary academia, disasters are seen as the consequence of inappropriately managed risk. These risks are the product of a combination of both hazard/s and vulnerability. Hazards that strike in areas with low vulnerability will never become disasters, as is the case in uninhabited regions.