Oftentimes, trains can stretch for miles and haul well over one-hundred cars. Many might wonder if every car on the train has brakes, and how something that heavy can come to a stop.
So, do train cars have brakes? Yes, every car on a train has its own set of brakes. This is made possible by an air line that spans the entire length of the train. Each cars has a set of brakes, air lines, and cylinders, which regulate the brakes on each car by responding to the commands of the engineer.
When air brakes were first implemented in the 19th century, their use revolutionized railroad operation, making it a safer, more effective way to travel. Below I explain who invented the air brake, and how trains operated prior to its implementation.
With the rapidly growing rail industry in the mid 19th century, trains were becoming the staple for transportation throughout the world, thus, trains were getting heavier and more frequent. However, the technology utilized by the railroads were becoming significantly outdated, which made for treacherous conditions for both passengers and crew alike.
Invented by George Westinghouse in 1869, the air brake became the standard in the railroad industry. Westinghouse realized that the budding rail industry was the face of the future, thus, safety needed to be at the highest priority. Westinghouse implemented his triple-valve air brake system, which was promptly implemented on railways throughout the world, and became the standard in the industry. The addition of the air brake allowed for faster train speeds, reduced travel time, and exponentially increased the safety within the industry.
Westinghouse, who frequently utilized the budding railroads, was aboard a passenger train in 1846, which had been delayed due to a collision involving two trains ahead. This caused Westinghouse to question the integrity and safety of the system, and believed an improved system, where a train could be stopped by an engineer in the cab could be implemented.
When Westinghouse patented his revolutionary air brake system, the Westinghouse Air Brake Company was formed to produce and distribute his products. Westinghouse’s first air brake system was patented in 1869, which was the direct air brake, where each car was connected via air hoses, where the engineer controlled the braking power for the entire train. However, a flaw of the direct air brake was that in the event that the air hoses disconnected or leaked between the cars, the system would be rendered inoperable, causing the train to lose its braking power completely.
However, Westinghouse built upon this idea, and developed the automatic air brake system, where the air brakes applied automatically in the event of a leakage or disconnect. This fail safe system improved safety and made the rail systems increasingly attractive, as a safe, efficient, and fast way to travel.
Before Air Brakes
Prior to the implementation of the air brake, brakes on each car had to be applied manually. An employee called a brakeman would run along the roof of the train, applying the brakes on each car by spinning the brake wheel. This was a dangerous profession, as walking atop a moving train was a tedious task, and risked falling from the top of the car. The job was increasingly risky during adverse weather conditions such as rain and snow, as visibility was scarce and the top of the railcars were slippery.
When a train needed to make a stop, the engineer would move the regulator to zero, and blow the whistle to alert the brakemen to apply the brakes on the rest of the train, a brakeman from the locomotive and caboose would sprint atop the train, applying each car’s brakes manually. Sadly, many brakemen perished, as there were 1,000 brakeman fatalities, and 5,000 injuries annually. Because of these statistics and the dangers of the job, there was a high turnover rate, as many brakemen realized the risks.
Many engineers and inventors in the United States and England searched endlessly for an alternative to the then current procedure. However, although many patents were awarded for an alternative braking design, they had mediocre performance, therefore, were not universally adopted.
This practice proved dangerous for passengers alike, as accidents were frequent, and braking power was scarce due to the inconsistency of the brake being applied. Trains would often overrun stations and crash into other trains due to the substandard braking capability. These accidents were oftentimes deadly, and made train travel a dangerous and unnerving affair, thus, many were skeptical about traveling by rail.
The need of a continuous train-brake, operated from the locomotive and under the immediate control of the engine-driver, had been emphasized through years by the almost regular recurrence of accidents of the most appalling character.” Charles Francis Adams. (air brakes turning point)
Although Westinghouse was not the first inventor to suggest air brake technology on the railroad, he was the first to be awarded a patent, and create a working model of the system. Westinghouse invited railroads to experience the model, and decide whether they would like to implement the system. Eventually, a subsidiary of the Pennsylvania Railroad experimented with the new technology. Realizing its imminent success, railroads began adopting the system as standard and implementing the system throughout their network. Furthermore, with Westinghouse’s patent on the air brake in 1869, a new chapter began for railways throughout the world, as safety and reliability would soon become cornerstones in the rail industry.
How Do Airbrakes Work
Air brakes are a relatively simple system. The locomotive and each car on a train has an air line hose and a cylinder to hold the air. With automatic air brakes, when the air is released from the cylinder, the brakes apply. This process is controlled by the engineer in the cab of the locomotive, who controls the brakes via a control handle, which controls the flow of air into or out of the system.
The control handle has various levels of braking; release, which in an automatic system fills the cylinders with air. Lap, which is a partial release, Application, which in an automatic system, empties the cylinders, causing the brakes to apply. Finally, emergency braking rids the cylinders of air as quickly as possible, also called “dumping the air”, which causes an immediate application of the brakes. (Railway Technical Website)
Air pressure is utilized to charge reservoirs in the tanks on each railcar and locomotive, when the tanks are full, the brakes are released. When the air pressure in the brakes is slowly reduced by the engineer, the brakes are applied but not at full service, when the engineer applies the brakes completely (full service), the air cylinders on the locomotive and each car are applied.
Straight Air Brake
The straight air brake lacks the fail safe system of the brakes being applied upon a loss of air, which would prohibit braking completely. This is the simplest form of air brake, as the compressed air is pushed on a piston located within a cylinder. This type of air brake system works by when the engineer applies the brakes from the cab, the system fills with air, thus, signaling to each car to apply the brakes. This differs from the automatic air brake, where a lack of air applies the brake.
Automatic or Westinghouse Air Brake
The automatic air brake system developed by Westinghouse includes a control valve or “triple valve” and an air reservoir on each piece of rolling stock. This type of brake includes the fail safe system where if the system loses air, whether due to a leak or any other event, the brakes will apply.
According to “The Railway Technical Website”, each cylinder on a piece of rolling stock has a piston within, which pushes the air out of the cylinder, and forces the brakes to apply. Inside each cylinder, attached to the pistons is a chain called “rigging”, which applies the brake blocks to the treads of the wheels. Because each piece of rolling stock depends on the air pressure located inside the triple valve on the car before it, an auxiliary reservoir stores reserve air to ensure their is ample air in the system to apply the brakes.
Hence the name triple valve, it is compiled with three valves, a slide valve, a regulating valve, and a graduating valve. The slide valve has an important function, as it ensures that the auxiliary generator is charged with ample air and allows the brake cylinder exhaust to dissipate. Furthermore, it drains the auxiliary generator and closes the brake cylinder exhaust if necessary. Additionally, the slide valve has the ability to hold the brakes at the application level set by the engineer. (The Railway Technical Website). An updated triple valve, called a distributor, are oftentimes utilized on passenger trains, and includes a graduated release function.