Europe Is the Last Region on Earth That Does Not Use DAC! The Evolution of Freight Transport Began in America

Automatic digital coupling (DAC) is a hot topic in the European transport sector. The cradle of this technology is America, and believe it or not, Europe is perhaps the last place in the world not using DAC.

In the context of the development of the European DAC system, it is often said that the European area is the last area on earth that does not yet have this technology. The cradle of automatic coupling, without knowing it, is probably the United States of America (USA). Here, railways were the first to replace primitive couplings and pins. Before this could happen, the switchman had to put the pin through the iron loop coupling at the right moment. Thousands of railwaymen were injured or lost their lives.

The Federal Safety Appliance Act, as early as 1893, stipulated that the coupler must self-couple after impact without a person having to enter the space between the cars. The Act itself spurred numerous inventions and designs, but the industry soon came to prefer the Janney coupler, patented in 1873 and adopted as the standard by the Association of American Railroads in 1916, including standard interchangeable parts.

Major Eli Janney, a Confederate veteran of the American Civil War, invented the semi-automatic articulated coupler in 1868. The locking pin, which ensures that Janney's couplers remain attached to each other, is manually pulled by a worker using a "cutting lever" that is operated from either side of the rail car and does not require the railroad worker to move between cars. The only time the worker had to pass between the cars was after they were securely coupled, to connect the air line for the air brakes or the main power cable in the case of the passenger cars.

The device of the American automatic coupler resembles a clasped hand, which is automatically coupled when one or both joints are open and the cars are pressed together. On impact, the joint rotates to the closed position, and the lock clicks into place, securing the coupling. The cars are uncoupled by lifting a lever that extends from the coupler to the side of the car so that personnel do not have to be in the space between the cars.

This type of coupler has gradually made its way to Japan, Australia, and many African countries, thanks to the strength of American industry. But why hasn't the American coupling penetrated Europe? By the first decade of the 20th century, various solutions were being compared, but none of them was found to be fully suitable for Europe. Like it is today with the Digital Automatic Coupling (DAC), the ability of trucks to accommodate the coupling in space and design was assessed. In continental Europe, two-axle wagons with relatively long overhanging ends were used.

The automatic coupler in the US has further evolved since the 19th century in terms of safety and railroad accident experience, especially in the key coupling part, improved metallurgy, repair and service techniques, and manufacturing process.

Further coupling research now falls under the purview of the AAR (Association of American Railroads) and the Institute for Railroad Progress, which has formed a special committee on coupling issues. The AAR publishes a manual of recommended practices for coupler use and maintenance along with standards for coupler replacement. The Association also includes couplers covering several freight car components in its quality assurance programs. All coupler manufacturers are certified directly by AAR auditors.

The automatic coupler has undergone several changes since 1873, yet the current coupler still has much in common with the current AAR coupler. Today's AAR coupler looks like a Master Car Builder Association (MCBA) type coupler, with the biggest change being in the coupler head joint itself. However, there are different types of couplings. The 'E' coupling, which is derived from the AAR coupling and the MBCA coupling, and the 'F' or tooth and socket coupling, is a variant of the coupling whose head is fitted with a mandrel and sleeve at the sides to prevent the couplings from moving vertically together, which can lead to the train becoming unstuck in the event of a derailment.

These couplings are used in particular on wagons with hazardous materials and wagons for unloading on rotary tippers without uncoupling the train, where one of the coupled couplings is always rotatable. However, they are couplable with type E. The last type is the American Public Transportation Association 'H' coupler, which is a variant of type F and is used exclusively on passenger cars. These couplers are also equipped with air and electric couplers.

What is the next expected US approach to automatic couplers? Very sober, one might say. The US attitude towards the promotion of new technologies is reinforced by the observation of developments in Europe. Yet, according to Railway Today magazine, the Americans feel that "our European counterparts may leapfrog us with a technology called DAC." Therefore, AAR is also making grants to further research and development that would bring American couplers technologically into the 21st century. However, we will have to wait for the development.