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Route capacity
Route capacity is the maximum number of vehicles, people, or amount of freight than can travel a given route in a given amount of time, usually an hour. It may be limited by the worst bottleneck in the system, such as a stretch of road with fewer lanes. Air traffic route capacity is affected by weather. For a metro or a light rail system, route capacity is generally the capacity of each vehicle, times the number of vehicles per train, times the number of trains per hour (tph). In this way, route capacity is highly dependent on headway. Beyond this mathematical theory, capacity may be influenced by other factors such as slow zones, single-tracked areas, and infrastructure limitations, e.g. to useful train lengths.
Any assessment of the effectiveness of a transport network includes a calculation of what capacity is used, how it is used, and whether it is used effectively. For instance, overloaded routes may need to be upgraded, or capacity provided by other routes. Unused capacity can represent an opportunity to move more people or goods: as the capacity exists no additional investment is needed. Many transport networks have unused capacity.
External factors affect route capacity in different ways. Severely overcrowded highways will reduce the capacity of bus services. Severe snowfalls will reduce the capacity of highways and freeways, and high winds will make landing and departing airports difficult. In many cases route capacity will vary day to day depending on external factors. Rail systems are more rarely affected by external factors.
Routes can become congested where only a fraction of routes can accept certain traffic types. For example, a road may have a low bridge that restricts the height of any trucks (lorries), or a rail line may be unable to accept wagons loaded beyond a certain axle load. This will result in any route that can accept a wider range of vehicles being congested, and other more restrictive routes be underutilised. Rail traffic between the US and Mexico is limited by the types of vehicles, especially grain wagons, and as 2009 the only routes that could accept newer rail wagons passed through Texas.
Bottlenecks play a large role in determining route capacity. Along any route the capacity is limited to the point with the lowest capacity, and long routes may have their capacity compromised by one bottleneck. Where more vehicles enter a route than a single bottleneck can accept, then the route will be free of congestion at all points except at the bottleneck. For this reason bottlenecks are often the focus of transport improvement projects.
Route capacity is often calculated and applied in the management and design of rail systems. For railways with very high passenger loads, the maximum possible route capacity is an important factor. A common unit for route capacity is people per hour (pph), which can for metro style systems can be as high as 80,000.[citation needed] Route capacity can also be expressed as number of vehicles per hour, such as 16 trains per hour (tph). Route capacities in rail lines with two tracks are almost always the same in either direction.
The maximum speed or average speed of rail traffic will have no impact on the route capacity where all train services are of the same type, and the stopping patterns are the same.[citation needed] Whilst slower trains will mean passengers take longer to reach their destination, the number of trains moving past a specific point will remain the same.[citation needed] Route capacity at a particular period of time can be observed by an observer standing on a station platform. A slower rail system will require more rolling stock to maintain a high throughput of trains. The speed of traffic will affect the required headway between trains (it is not simply proportional to the speed) and will thus affect the route capacity.
In calculating route capacity it is important to consider practical considerations. Many railways will wish to operate at the maximum capacity for hours on any given day, and the theoretical capacity is not sustainable for more than a few trains.[clarification needed] A reduced level of capacity, which can be maintained for hours, is often calculated. A railway that operates at close to the level of theoretical capacity for extended periods will have lower punctuality (fewer trains arriving when timetabled).
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Route capacity AI simulator
(@Route capacity_simulator)
Route capacity
Route capacity is the maximum number of vehicles, people, or amount of freight than can travel a given route in a given amount of time, usually an hour. It may be limited by the worst bottleneck in the system, such as a stretch of road with fewer lanes. Air traffic route capacity is affected by weather. For a metro or a light rail system, route capacity is generally the capacity of each vehicle, times the number of vehicles per train, times the number of trains per hour (tph). In this way, route capacity is highly dependent on headway. Beyond this mathematical theory, capacity may be influenced by other factors such as slow zones, single-tracked areas, and infrastructure limitations, e.g. to useful train lengths.
Any assessment of the effectiveness of a transport network includes a calculation of what capacity is used, how it is used, and whether it is used effectively. For instance, overloaded routes may need to be upgraded, or capacity provided by other routes. Unused capacity can represent an opportunity to move more people or goods: as the capacity exists no additional investment is needed. Many transport networks have unused capacity.
External factors affect route capacity in different ways. Severely overcrowded highways will reduce the capacity of bus services. Severe snowfalls will reduce the capacity of highways and freeways, and high winds will make landing and departing airports difficult. In many cases route capacity will vary day to day depending on external factors. Rail systems are more rarely affected by external factors.
Routes can become congested where only a fraction of routes can accept certain traffic types. For example, a road may have a low bridge that restricts the height of any trucks (lorries), or a rail line may be unable to accept wagons loaded beyond a certain axle load. This will result in any route that can accept a wider range of vehicles being congested, and other more restrictive routes be underutilised. Rail traffic between the US and Mexico is limited by the types of vehicles, especially grain wagons, and as 2009 the only routes that could accept newer rail wagons passed through Texas.
Bottlenecks play a large role in determining route capacity. Along any route the capacity is limited to the point with the lowest capacity, and long routes may have their capacity compromised by one bottleneck. Where more vehicles enter a route than a single bottleneck can accept, then the route will be free of congestion at all points except at the bottleneck. For this reason bottlenecks are often the focus of transport improvement projects.
Route capacity is often calculated and applied in the management and design of rail systems. For railways with very high passenger loads, the maximum possible route capacity is an important factor. A common unit for route capacity is people per hour (pph), which can for metro style systems can be as high as 80,000.[citation needed] Route capacity can also be expressed as number of vehicles per hour, such as 16 trains per hour (tph). Route capacities in rail lines with two tracks are almost always the same in either direction.
The maximum speed or average speed of rail traffic will have no impact on the route capacity where all train services are of the same type, and the stopping patterns are the same.[citation needed] Whilst slower trains will mean passengers take longer to reach their destination, the number of trains moving past a specific point will remain the same.[citation needed] Route capacity at a particular period of time can be observed by an observer standing on a station platform. A slower rail system will require more rolling stock to maintain a high throughput of trains. The speed of traffic will affect the required headway between trains (it is not simply proportional to the speed) and will thus affect the route capacity.
In calculating route capacity it is important to consider practical considerations. Many railways will wish to operate at the maximum capacity for hours on any given day, and the theoretical capacity is not sustainable for more than a few trains.[clarification needed] A reduced level of capacity, which can be maintained for hours, is often calculated. A railway that operates at close to the level of theoretical capacity for extended periods will have lower punctuality (fewer trains arriving when timetabled).