Trains are a great means of transportation for people all over the world. They go through a variety of regions and landscapes, whether it be deserts or forested areas. But have you ever wondered whether trains could go uphill?
Well, they technically can, but with incredible difficulty. Conventional railway systems can allow trains to go uphill by a grade of only 3%. However, with the use of railways designed for uphill slopes, trains can indeed go uphill much more easily.
Now that we’ve got that out of the way, let’s go into more detail about trains going uphill, including how you measure it.
Can a Train Go Uphill?
If trains can’t climb hills, they’re virtually useless as a mode of transportation. Without intervention and the deployment of supporting measures, the trains could only run up relatively minor inclines because of their heavy weight.
Most mainline routes are designed by railroad engineers so that the maximum gradient is 4%. This equates to a 0.4-mile ascent in elevation for every 10 miles traveled. In some nations (like Switzerland), conventional procedures are employed on tracks with a greater grade (7%).
What is a Grade?
Grade is expressed as the number of feet of ascent for every 100 feet of level ground. The grade of a track is expressed as a percentage; 1 percent would represent a climb of 1 foot over 100 feet, while 2.5 percent would be a rise of 2 and a half feet.
Which Grade is the Most Steep?
The Pennsylvania Railroad north of Madison, Indiana reportedly had the highest grade of any major railroad’s mainline track (as compared to industrial extensions). The current gradient of the track, maintained by the short line Madison Railroad, is 5.89 percent (413 feet up over 7012 feet).
For a long time, the 4.7-percent slope of the Norfolk Southern south of Saluda, North Carolina main line was the steepest in the world. After Saluda’s retirement in 2002, BNSF’s 3.3% Raton Pass grade in New Mexico took the title of North America’s steepest main-line grade.
The Importance of Grades
Inclines have a major impact on train operations. A steady speed train encounters an extra 20 pounds of resistance for every percentage of incline. This is in contrast to the roughly 5 lb. per tonne of train resistance encountered on flat, straight track. Then, compared to its level-ground capacity, a locomotive can only transport half as many tons up a .25-percent slope. Equipment wear and tear and increased fuel consumption are just two of the costs associated with ascending gradients.
How Trains Go Uphill
A variety of methods are used to increase a train’s upward momentum. You’ll find brief discussions of a few of them below.
Helper Districts
Railroads will sometimes construct “helper districts” in areas with particularly steep gradients. In some areas, trains that lack sufficient locomotive power can rely on “helper locomotives” to make it over the incline.
Typically, these engines will head back to the lowest part of the gradient, which means that they will not be hauling any cars, in order to wait for the next train that will require their aid. These locomotives are often built for pulling capacity rather than speed, though occasionally locomotives that perform poorly in their primary roles are relegated to assistance service.
To help the main locomotive, a helper locomotive can be attached anywhere along the train’s length.
Double the Hill
If a train is unable to make a slope without assistance, “doubling the hill” (taking the train up the grade in two portions) may be used. Some hills need “tripling,” or traveling in threes.
Railways Designed for Steep Grades
Rack (or cog) or cable systems may be utilized when the gradient is too high for the more common railway system. Despite a few outliers, the U.S. rail network does not use any of these ways to traverse slopes.
Funicular or Pull Type Railway
A funicular combines elements of an elevator (a cable that raises a car) with a railroad to create a unique mode of transportation. Since its invention in the 15th century, the funicular has been used primarily to transport skiers to the summit of mountains. Inclined railways is a common term used to describe these systems in the United States.
First, a cable helps pull the vehicle up the mountain, eliminating the need to worry about traction. The car’s wheels do nothing more than propel it up the mountain. They provide nothing for the necessary pulling force.
Funiculars are ingenious in many ways, but the fact that they can use two cars at once, one on each side of the top pulley, is particularly brilliant. One vehicle always counteracts the other’s mass. The train heading up the mountain benefits from the descending car’s size, and the train going down the mountain prevents the descending train’s speed from getting out of hand.
There is still a motor driving the pulley, but it just needs to produce enough force to counteract the friction in the system and the disparity in mass between the two cars (which is caused by the weight of the occupants).
Cog or Rack Railway
The rack and pinion mechanism implemented was developed by Swiss engineer Dr. Roman Abt and is patented by the latter. Double rack rails are used on this railway and are attached to steel sleepers in the gap between the running rails. In order to gain the traction required to climb even the steepest inclines, each locomotive is outfitted with toothed pinions (cogwheels). The rack and pinion setup doubles as a brake for the descent.
For more information about rack railways, watch this video below:
What is Rack & Pinion Railway.
Adhesive-Rack Railway
Lines that employ rack systems can be divided into two groups based on whether or not the rack rail is continuous. Pure-rack lines are those that exclusively employ the rack rail and the cog-drive. Rack-and-adhesion lines are another type of railway that employs a cog drive solely on the steepest incline sections.
Trains that operate on rack-and-adhesion lines are outfitted with propulsion and braking mechanisms that are able to act either through the running rail wheels or the cog wheels, depending on the presence of the rack rail.
This allows the train to operate in either direction, regardless of whether the rack rail is there or not. A rack section positioned on a spring allows the pinion teeth to slowly take part, allowing for a seamless transition from friction to rack traction in rack-and-adhesion lines.
Conclusion
Being some of the oldest modes of transportation, there isn’t much that trains can’t do. But they do require the assistance of some external systems, such as certain kinds of railways or helper districts. Nevertheless, it’s clear that trains can indeed go uphill.
