Around 40 rail bridges cross the Mississippi River in the United States. The majority is located in Arkansas, Iowa and Louisiana. On the upper parts of the river, mostly in Minnesota and Wisconsin, one finds eight rail bridges, while the lower river states boast around 30. With railroads that stretch thousands of miles on the east and west coasts of the Mississippi, it is necessary to have bridges to cross the large expanse of the river.
Rail bridges are usually made up of three separate spans or sections. The first two are connected to each other and the final span connects the two together. Depending on the needs of the railroad, a bridge might have as few as two or as many as 10 spans. Typical bridge heights range from 60 feet to 120 feet, allowing plenty of room for boats, barges and river traffic to pass through without interference.
The first rail bridge across the Mississippi was built in 1856. This bridge was known as the Hannibal Bridge and it crosses the river at Hannibal, Missouri. Since then, a variety of new rail bridges have been built. For instance, the modern bridge that carries the Burlington Northern Santa Fe Railway across the Mississippi in St. Paul, Minnesota is a truss bridge made up of three spans with a total length of over 2,000 feet.
Since the 1800s, advancements in engineering and enhanced government regulations have led to stronger and safer rail bridges. Building a rail bridge over the Mississippi is particularly challenging because the river is wide and moves at a swift pace. A number of safety features must be incorporated into the design, including warning systems and barriers.
After the design and the construction of a rail bridge has been completed, it must pass rigorous inspections to ensure its structural integrity and functionality. Regular inspections, maintenance and repairs are necessary in order to keep the bridge and its components in excellent condition.
The numerous rail bridges that stretch across the Mississippi also offer numerous economic benefits. These bridges are used to transport goods, passengers and freight across the river, helping to grow the economy of the region in the process.
Environmental Impact
The construction of new rail bridges often has an environmental impact on the nearby habitat. Before a bridge can be built, the area must be cleared which could potentially affect the fragile ecosystems that exist in the region. Additionally, concerns about noise, air and water pollution are taken into account to ensure that the environment is protected as much as possible.
Once a bridge is in place, efforts must be made to limit the effect that it has on wildlife and the local environment. Accidents can occur if animals try to cross the bridge, so warning signs and fences are often used to keep them away. Regular inspections must also be carried out to ensure the bridge is functioning properly.
Cost Considerations
When constructing a rail bridge over the Mississippi, the cost is an important factor to consider. The cost of building a basic bridge is typically around $20 million. However, when more complicated design features, longer spans and more demanding safety requirements are taken into account, the total cost can increase significantly.
In addition to the cost of building a bridge, ongoing costs for maintenance and repairs must also be taken into consideration. Depending on the type of bridge and its location, these costs can add up quickly. It is important for railroads to plan for these costs in order to ensure that their bridges remain in good condition.
Construction Timelines
Another factor that affects the cost and construction of a rail bridge is the timeline. From the design phase to the construction and completion of the project, a bridge can take anywhere from one to five years to finish. Depending on the size and complexity of the bridge, the timeline can vary greatly.
In order to speed up the process, railroads must work closely with design and engineering firms to create a detailed construction plan. By working collaboratively, the construction process can be sped up and the risk of potential delays or complications can be minimized. Additionally, ensuring that all safety requirements are met will help to ensure that the construction timeline is not extended unnecessarily.
Alternative Methods of Crossing Rivers
Railroads have always used bridges to cross the Mississippi River, but other methods such as ferries and tunnels can also be employed. Ferries are often used to cross short distances, while tunnels are suitable for longer spans. However, of these three options, bridges generally offer the most efficient and cost-effective way to cross the river.
Ferries can be suitable for short distances, but they are limited by the size of watercraft available and the speed at which they travel. Tunnels are suitable for longer spans, but their construction can be costly and time consuming. By comparison, bridges are generally the quickest and most cost-effective way to cross the Mississippi River.
Governance and Regulations
In the United States, crossing the Mississippi River with a rail bridge is regulated by different federal and state agencies. In some cases, railroad companies must obtain permission from the Army Corps of Engineers and the Coast Guard before building a bridge. Additionally, federal and state governments will often require railroads to submit detailed plans and construction schedules to ensure that all the necessary safety requirements are met.
In order to comply with the regulations, railroads must ensure that they have the necessary expertise and resources in place. Additionally, they must ensure that their plans are up to date and that they are compliant with all the latest safety regulations. By meeting all the requirements, railroads can ensure that their bridges are constructed and operated safely and efficiently.
Real World Examples
One example of a rail bridge across the Mississippi River is the Homer E. Adams Memorial Bridge in St. Louis, Missouri. This bridge is made up of two central truss spans that are topped with a steel arch, allowing for a maximum clearance of 93 feet. The bridge was completed in 2014 and has been used by more than 40,000 vehicles per day since its completion.
Another example is the Rock Island Bridge in Rock Island, Illinois. This bridge is a double-track railroad bridge with two main spans that stretch over a mile and a quarter. The bridge was completed in 1907 and was used to carry freight and passenger trains across the Mississippi until it was decommissioned in 2014.
These two examples show the complexity and scale of some of the rail bridges across the Mississippi River. By taking into account factors such as construction costs, timelines and safety regulations, railroads can ensure that their bridges are safe and efficient.
