N gauge trains


How N Scale Couplers Variations for Model Railroads

N-scale is one of the most popular scales that modelers work on. It ranges from 1:148 to 1:160 depending upon the country and the manufacturer of the train. In this scale, the distance between the rails of the train is 9 mm (equivalent to 0.354 inches). In the UK, the term N gauge refers to 1:160 (9 mm) track gauge modeling on a 1:148 scale.

Even though the terms N-gauge and N-scale are used interchangeably, they do not mean the same thing. While the term N-scale means the proportion of ratio to be used in the model, the term N-gauge technically refers to the gauge distance between the rails of the train. For ease of material exchange, the scale of 1:148 is used for rail to rail gauge.


n scale couplers



Even though both of these are N scale couplers, they are not compatible with each other. Knuckle couplers are more recent, and are available in a wide range. All of these varieties of knuckle couplers are incompatible with Rapido couplers, and most, are incompatible with other brands of Knuckle couplers. Rapido couplers are considered the original N-scale couplers.

Types of N Scale Couplers When building a model railroad, it is important to consider N scale couplers. Once the scale of the model is determined, the next step is to ensure the couplers on the locomotives and the cars available are compatible. In the N scale setting, there are mainly 2 types of couplers:

1. Rapido

2. Knuckle

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How Couplers Work

In real life and on model railroads the function of couplers is to join the engine (locomotive) to the car directly behind it, and then to join each car in the train to the car directly in front of, or behind it.

knuckle coupler

Knuckle couplers where invented by Major Eli Janney, a Civil War veteran, in 1868. The knuckle coupler would best be described as a semi automatic device that closes and locks the cars together. The closing operation needs to be safe and efficient to properly lock the cars without them coming lose and derailing or running wild, and without endangering any rail workers that might get between the cars.

On real railroads safety is paramount as a worker can be easily injured or killed through inattention or faulty equipment. The original ‘link & pin’ coupler was a big cause of rail worker injuries. The ‘cut’ lever in the corner of cars releases the couplers knuckle to make the uncoupling much safer.

When you think about it, railroad cars need to get coupled and uncoupled hundreds or thousands of times throughout the life of each car. For that reason the coupling mechanisms need to be very sturdy, efficient, and reliable. Over the period of its life a car will be connected to a multitude ode different cars or locomotives, so it makes sense for the couplings to be standardized and compatible with all cars. It makes sense for the couplers to be at the same height and position on every car. Unfortunately the system is not that simple and some variations do exist between coupler types. That said; there is a high level of standardization with the common types in many parts of the world.

train couplers 



Note: I am not very good at drawing so these sketches are only a rough indication of how train couplers work.

These three drawings show the basic process of how two couplers are coupled together. The knuckles on the couplers must be open to couple the two cars. When the cars are shunted together, the two knuckles close onto each other. They are then locked from the rear with a vertical pin that drops a steel block into position just behind the raised casting of the knuckle. For uncoupling, a pin is pulled up releasing the block that is locking the knuckle in place. This operation is performed using a lever (or chain) from the car side.

Rapido Couplers

While most sources claim that the original N-scale couplers were made by Arnold and Rapido, there are also sources that say Trix was also working on similar products on the same scale at that time. It is believed, and is evident, that other manufacturers were allowed to use the Rapido coupler design. This was the reason why early N scale couplers were compatible with products from different manufacturers. Since the Rapido couplers were the first in line, they left much to be desired. Plain and simple, they were just square hooks, and did not resemble real-life couplers at all. Also, most modelers use tools to couple and decouple the couplers. But the Rapido coupler can only be decoupled by hand.

These days, while most manufacturers are designing products with knuckle couplers, there are still a few who use Rapido couplers.



This image shows the top view and side profiles of common couplers. Please note the images are not exactly to proportion, but they give a good comparison of how each coupler looks.

n-scale couplers

N scale steam locomotives

Click this image to watch a quick N scale video.

MTL Couplers (Kadee Magne-matic Couplers)

Originally HO couplers, Kadee’s Magne-Matic couplers are now also available in N scale, and are called MTL couplers. Kadee’s Magne-Matic couplers were first introduced in the HO scale in the 1940s. It was around the 1960s when the company came up with the first N-scale coupler. The subsequent division and separation of the company into two separate companies lead to the original company manufacturing larger scales, including Ho, and the new company, Micro Trains Line manufacturing smaller scales including N- scale. The company’s N-scale couplers, called MTL couplers, are still one of the most popular couplers for the N scale.

Most knuckle couplers are magnetically controlled. But most modelers prefer to uncouple by hand. This is because of the reason that placing magnets along the tracks on a model railroad can lead to breakaways (unwanted uncoupling). Also, uncoupling by hand allows the uncoupling to be done at any point on the track on not just the specific places where the magnets have been placed.

Knuckle Coupler Brands

MTL’s knuckle couplers were patented and the decision of other companies to not pay them the royalties led to emergence of newer brands of knuckle coupler brands. Knuckle couplers are designed to look more like the real couplers and hence, are more preferred than Rapido couplers. Major names in the knuckler coupler manufacturing are: Atlas, Kato, Red Caboose, Intermountain Railway, and Roundhouse. These companies manufacture and offer their own brands of knuckle couplers. The most recent addition to this list is that of Athearn Trains, who acquired McHenry. Expanding the original HO line, they have recently started manufacturing N-scale couplers also. Fleishmann is a well loved and popular brand in Europe.

n gauge couplers

Kinematic Couplers

Kato has introduced the “kinematic” coupler for their Morning Daylight passenger trains. This knuckle coupler is incompatible with any other knuckle coupler. Designed to close the gap between the passenger cars, it allows for the required extension on turns and bends.


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n scale layouts book


Problems With N-Scale Couplers

The first and foremost problem with N-scale couplers is that there are so many. The sheer variety and the brands is enough to confuse anyone.

Once which one to use is decided, the next problem that arises is the conversion. While most manufacturers now design their products with the knuckle couplers, there are still manufacturers who manufacture using the Rapido couplers. While most knuckle couplers are compatible with other varieties, there are some brands that are incompatible. Also most Rapido couplers are not compatible with any knuckle couplers.

The conversion of the coupler is thus an important task. Most modelers consider it easier and more convenient to use the truck mounted couplers to the body mounted couplers. Another solution to this problem is to look for conversion tips on the internet. A modeler can also look for local modeling groups for help with the conversion and the modeling.

Another problem with the N-scale couplers is the compatibility. All the couplers of the model train need to be the same kind, and if not, it is a task to figure out compatible brands of couplers.

While Rapido couplers are also easily available, they do not look authentic and defy the main element of realism of the model railroad. On the other hand, knuckle couplers look and perform much more like the real-life couplers. Hence, most modelers prefer the knuckle couplers over Rapido couplers to sustain the realism and authenticity of the model.

Rapido coupler can only be uncoupled by hand. Also, while knuckle couplers are easy to use, and can be magnetically uncoupled, most modelers prefer uncoupling by hand. The placement of magnets on the track to pull the trip pin and create the uncoupling can sometime not work as planned and lead to breakaways. Hence, the choice to uncouple by hand to allow the freedom to uncouple anywhere on the track.



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