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Link and Pin Couplers

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link and pin couplers

The link and pin coupler is simple, but offers a very small margin of error. Links were kept short to reduce slack.

©2010 Ryan C Kunkle, licensed to About.com, Inc.

Link and Pin couplers became a symbol of the perils of railroading in the Nineteenth Century. From the 1830s to the 1880s, the simple link and pin coupler was the most practical method of semi-permanently attaching train cars. Responsible for unknown thousands of injuries and deaths, the technology became illegal in the United States on mainline railroads with the passage of the Railway Safety Appliance Act in 1893. With the addition of safety buffers, link and pin couplers remain in use in other parts of the world to this day.

How It Works

An iron loop, or link, is inserted by hand into a pocket on one car and secured with a large iron pin. The brakeman then holds the link in one hand an a second pin in the other while the next car is pushed into position. At exactly the right moment, he must let go of the link and insert the second pin into the pocket of the oncoming car.

Early cars had no means of cushioning the impact so if the brakeman's timing was off, he could loose fingers, a hand, or even be crushed completely between the two cars. Cars could not always be coupled when stopped because stopping in exactly the right position took time and was not a simple task on equipment that lacked air brakes.

In addition to the human cost, link and pin couplers produce a lot of slack action, have limited strength and are time consuming to couple and uncouple. Ultimately, they are as inefficient as they are dangerous.

Why Didn't Railroads Convert Sooner?

Despite the human tragedy and operating inefficiency of the link and pin, railroads were slow to convert to new coupler designs. Many blame the delay on greedy railroad executives choosing profit over safety. While cost was certainly an issue, it was not the only issue. Although Eli Janney is credited with the patent for what ultimately became the new standard coupler in 1873, the decision was not as simple as Janney vs. link and pin.

Numerous patents were issued in the 1870s and 1880s for new couplers. Like the Westinghouse airbrake, multiple inventors were trying to make a name for themselves by solving these problems. For railroads, the problem was one of quality and quantity.

Which technology would become the new standard? And would every railroad adopt it? The conversion would have to take place quickly and universally. Imagine converting all of the cars on your railroad to a new type of coupler. Cars with the old couplers will not work with cars with new couplers.

Now imagine that you and your friends regularly swap (interchange) cars. Your friends must also convert all of their cars to the new couplers as well. Now let's assume there are about six hobby manufacturers making the "best" new design and each of you likes something different. Now make those couplers full-scale and assume you've each got several thousand locomotives, freight and passenger cars to convert.

Anyone who has ever been in a club considering a conversion to DCC can understand the frustration. Getting all of the railroads to agree to one design and one time was beyond the means of private industry. The United States Federal Government finally stepped in and set the standards.

Modeling Link and Pin Couplers

Although model trains don't pose the safety hazards of the prototype, the operational limits of link and pin couplers do remain. Working and non-working link and pin couplers are available in some scales. Making your own from scratch however would not be that daunting a project. If your modeling interests include the types of equipment that would have used link and pins, chances are you're used to not buying everything you need ready-to-run.

Link and pins would be better suited in larger scales. Not only will it be easier to build them to scale, hands-on operations will be greatly simplified. Just getting your fingers between a pair of N-scale cars can be a challenge, let alone inserting a tiny pin in a miniscule loop.

Remote control or magnetic uncoupling will also not be an option. Of course, slowing down the operations to couple and uncouple each car has many advantages. Just make sure you'll be able to easily reach every siding and spur where you'll be spotting cars.

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