How Does a Model Train Work?

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Model trains have been popular additions to many homes for decades, ever since Lionel created the first electric version in 1901 to dazzle the eyes of children passing by storefront windows. Trains today come in endless varieties, sizes, and styles, but they all have the same standard operations.

A model train works by sending an electrical current from a wall outlet into the tracks, through the wheels, and to a motor that powers the train. The motor turns a screw and cog, which rotates the axel and makes the train move. The model train’s track looks and works just like a real train track. 

In this article, I’ll explain in detail how model trains are powered and how they operate. I’ll also discuss some of the different types of model trains available on the market today.

How Does a Model Train Work?

Powering a Model Train

While there are some battery-powered trains on the market, they’re mostly considered children’s toys and aren’t the same quality as a model train. Most models are powered by electricity from your home’s wall outlet. 

Let’s take a look at the parts of the train’s electrical system. 

The Transformer

The power cord has an attached transformer that changes the current of electricity coming from the wall. This is why you’re able to touch the train track once you’ve run power to it without getting shocked. 

The Controller

A controller controls the power coming from the transformer that’s fed to the track. It acts like the gas pedal in your car – the car is constantly receiving power, but it doesn’t move until you press the gas pedal. 

The Tracks

The wires from the controller are connected to the track by a power feed. These can be attached by a clip or soldered into place, depending on the manufacturer and type of model. 

According to Model Railroader, “good electrical connections are a key to a smooth-running model railroad.” Watch this video on YouTube about attaching feeder wires to the model train’s track for more information:

To attach the track segments and make sure the electrical current can pass through, a metal clip called a “fishplate” is used. The joints on real train tracks are also called fishplates. 

Model Train Circuitry 

Each rail of the train track has a different electrical current – one is positive, and one is negative. When the train’s motor is powered, an electrical signal travels from the controller to the train’s motor, and the wheels move.  The opposite rail completes the circuit, where power travels back to the controller to close the circuit.

Switching the controller to the opposite direction reverses the electrical current’s flow, which allows the train to move forward and backward on the track. This simple direct current (DC) system means that all trains on the same track must move in the same direction, at the same speed, at the same time. 

More modern designs include Digital Control (DCC) models. In this setup, each individual locomotive has a mini-computer inside that the controller communicates with through the power signals on the track. This allows the operator to control each train individually based on their settings. 

For a great starter train that you can run right out of the box with these advanced features (including Bluetooth technology), I recommend this Lionel Santa Fe Set .

Lionel Santa Fe Super Chief LionChief Set with Bluetooth Capability, Electric O Gauge Model Train Set with Remote

You can even control this train with your mobile device! It’s great for beginner hobbyists or a child that’s interested in a more realistic train set.

For more information on model train circuitry, check out the YouTube video below by That Model Railway Guy, where he explains how to wire a model railway from start to finish:

Then, once you’re ready to start building, take a look at Andrew Duckworth Electronics and Wiring for Model Railways is an excellent resource for getting the layout and circuitry right, which is always one of the biggest challenges for hobbyists. 

How a Model Train Motor Works

  1. When the motor receives power, it turns a screw mechanism called a worm drive. 
  2. he screw is connected to a gear, called a worm gear, that turns the axels to the wheels. If the train has a smoke unit, it may also turn a gear connected to a bellows that controls the smoke, making the puff of smoke come out faster as the train moves more quickly. 
  3. The mechanisms are housed inside a gearbox, where the motors can be mounted horizontally or vertically, depending on when it was manufactured and the design. 

Watch this YouTube video by Sam’s Trains to see different types of motors over the years and see what the inside of a model train looks like:

How a Model Train Track Works

A model train track is a miniature version of a real train track. The wheels sit on the track the same way that a full-size locomotive does. 

  • Each rail of the track is held a set distance apart by sleepers, also known as railroad ties. There is usually always a sleeper between the rail tracks to maintain the correct gauge. The gauge determines which size trains are compatible with the track. Gauge isn’t the same as scale.
  • Each wheel has a lip that sits on the inside of the track, so the train doesn’t run off the track, similar to real locomotives. This lip is called a flange. However, the train may still come off the track if it’s not sitting on a flat surface. 
  • Model railroad tracks are coded with a number that designates the scale. These codes are defined by the National Model Railroad Association (NMRA). The code number refers to the height of the track in thousands of an inch.  Code 80 would indicate .080″ (2.03 mm) high, for example, and code 55 would mean the height is .055″ (1.39 mm). Code 83 is among the most popular used among model railroad builders today.
  • The letters on model train track codes indicate a scale mile or a mile of length scaled down to the correct proportion. Some of the common scale miles include:
    • N = 33 ft (10.06 m)
    • O = 110 ft (33.53 m)
    • HO = 60.7 ft (18.50 m) 
    • S = 82.5 ft (25.15 m)

Model Train Scale

Model train scale standards are regional and are defined by an official organization that operates in the hobbyists’ area. 

For example, in Europe, the MOROP publishes NEM standards for scale. Scale is the proportion or ratio of the model train to the actual train, known as the prototype.

In the United States, the NMRA published a standardized scale system in the 1940s. The two scales are similar but do have a few differences. 

Here’s the standard NMRA scale used by most model railway builders in the US, showing the scale, scale to foot, and proportion:

O(17).266” (6.75 mm)1:45.2
O, On2, On3.250 (6.35 mm)1:48
S, Sn3.188” (4.76 mm)1:64
OO.1575” (4.0 mm”)1:76.2
HO, HOn2, HOn3.1378” (3.5 mm)1:87.1
TT, TTn3.100” (2.54 mm)1:120
N, Nn3.075” (1.90 mm)1:160
Z.055” (1.39 mm)1:220

What’s the Difference Between Model Train Scales?

If you’re going to build a model train, one of the first decisions you need to make is which scale you’re going to use.

Model train scales vary in size and compatibility with tracks and other equipment. Some scales are more common than others, so there’s more variety of materials to choose from. 

For example:

  • Z scales are the smallest, and there are fewer options than the HO scale, though they’re unique for their precision at such a small size.
  • HO scales have the largest selection available and are one of the most popular scale sizes. HO stands for “half O,” which has more detail and a wide range of accessories available for an ideal model train experience.
  • S Scales run on a two-track system, while the O Scale runs on a three-track system. These multi-track layouts allow for more complex displays and the ability to run multiple trains.
NOTE: The larger your train’s scale, the more space you need to create a realistic and expansive layout. Many people start with a full set at their preferred scale before purchasing individual train pieces. 

This LGB Freight Set is ready to run right out of the box. It includes 12 pieces of curved track, light, smoke, and sound.

LGB Freight G Scale Starter Set with Sound - 120 Volts

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