To build a model train, first decide on which gauge, or track width, to use. Next, choose the scale of the railroad; HO scale is the most popular choice for model railroading. Other common model railroad scales include O scale, O27 scale and S scale.
Plan the setting of the railroad, including the time period, purpose of the railroad and landscape details. This helps determine the types of trains to use. For example, an old-fashioned railroad may have steam engines, while a more modern setting can feature diesel trains. An industrial railroad requires freight or service cars, while a passenger railroad employs coaches. A cityscape may include trolley cars or other passenger vehicles.
To better visualize the layout and more easily change the design, put the track sections in place without attaching them. Some builders draw the layout on paper before laying the track. Leave some straight track between curves so that trains do not derail. Ensure that the trains have enough space to clear tunnels and landscape features, such as trees, bridges and mountains. After troubleshooting the layout, join the track together and glue it down.
Decide on what style of wiring enhances the layout; options include block wiring, cab control and digital command control. When wiring the model railroad, label the positive and negative wires to prevent a short circuit, and never connect positive rails to negative ones. Larger setups may benefit from circuit breakers, which prevent a power outage from affecting the entire railroad. Railroads with more than one train require a separate transformer for each engine.