Why Trains Run on Tracks Rather Than Roads
In the world of transport, trains are uniquely suited to run on tracks rather than roads, which is why we find them dominating heavy-load transportation while lorries or trucks handle individual or smaller deliveries. This article explores the reasons behind this choice, focusing on efficiency, durability, and historical context.
Efficiency and Resistance
The efficiency of trains running on tracks is largely due to the minimal rolling resistance compared to road vehicles. Traditional trams and trains have metal wheels and tracks, an arrangement that significantly reduces the friction against the ground. This low resistance allows trains to achieve high load-to-power ratios, which are crucial for cost-effectiveness and fuel economy. A 100-car freight train with 824 steel wheels can operate with a power-to-weight ratio of less than 1 horsepower per ton, making it incredibly fuel efficient.
Historical Context and Infrastructure Investment
Trains did not emerge overnight; they were the product of industrial revolution era innovations. Initially, horse-drawn carriages were the means of transport, which thrived well on dirt roads. The invention of the locomotive with power many horses (equivalent to many more horses) changed the game. However, the lack of smoothness in dirt roads posed significant challenges for trains, leading to the development of specialized tracks for better performance.
Decades later, as cars and horseless carriages (early automobiles) began to take over, the need for smoother roads increased, leading to the advent of paved roads. Nonetheless, trains had already established a solid infrastructure, with very strong railway tracks, guides, and bridges. Switching to roads would mean incompatibility with this existing, expensive, and highly durable infrastructure. Most importantly, roads are much less capable of supporting the massive weight of trains without collapsing.
The Impact of Rolling Resistance
The concept of rolling resistance is crucial in understanding why trains prefer tracks over roads. Rubber tires used by road vehicles, including cars and lorries, face considerable resistance when overcoming irregularities and obstacles in the terrain. This requires more energy to maintain motion and results in higher maintenance costs and fuel consumption.
In contrast, metal rail systems offer a smooth and stable surface, significantly reducing rolling resistance. The construction of the roadbed, along with the rigid structure of the trains, ensures that even very heavy loads, like those carried by freight trains, do not damage the tracks. Moreover, the metal components of the rail system can be replaced more easily and last much longer than the paving and maintenance required for road systems.
Modern Applications and Advantages
Today, the use of dedicated railway corridors, integrated signaling systems, and high-speed tracks further enhances the efficiency of train transport. Railway systems are designed as dedicated corridors, optimizing energy usage and providing a consistently efficient transport solution. Integrated signaling systems help manage congestion and ensure safe operation, which is especially important for the hundreds of passengers a single train can carry.
The smoothness and strength of rail tracks provide a more sustainable use of resources compared to the constant maintenance and frequent replacement of road surfaces. This makes the railway system a more environmentally friendly and economical choice, especially for long-distance and heavy-load transport.
Conclusion
In conclusion, the decision to run trains on tracks rather than roads is based on a combination of historical infrastructure, efficiency, and mechanical advantage. The specialized design of trains, the efficiency of metal on metal contact, and the investment in railways make it uneconomical and impractical to switch to road vehicles for mass transportation of goods and people.