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How to Wire a Model Railroad

Making model railroads is one of the most popular hobbies in the world. A model railroad is always made from products that are either available in the house or in store packages, unlike a toy train, which is bought ready to run. The scenery is an important part; it can resemble the heart of a small town or a rugged mountain range. The essential part of any model railroad is the wiring, which is the focus of this article. You can get simple wiring which allows only one train to run at a time, or a more complex setup for running two trains at once. Of course you will have to be careful to avoid a shock, so keep water away from the track.

Wiring should be a simple task as long as you have a terminal track and a suitable transformer, both of which you can usually buy at a hobby shop. You also need low voltage wire. First, unplug the transformer, attach the terminal track to the system and loosen the screws on the terminal. After stripping a half-inch of the sheathing from each end of a pair of low-voltage wires and bending all four into a hook shape, hook two ends around two of the screws of the terminal and the other two around those of the transformer. Then plug in the transformer and put a model engine onto the track. Once the power has been turned on, the train should move along the tracks just like a real one!

Color coding

Such are the basics of wiring. Let us now delve more deeply into some of the rules to follow when you perform the task.

One of the things you should have while you work is a color code in which each of the various components of the system is given its own special color. You can use any colors you want, but once you have established the code, stick to it! One model railroad hobbyist uses the following combination of colors for his items:
• DCC main bus: blue and gray
• DCC secondary bus: blue and black
• DCC rail feeder: blue and white
• 18V AC DCC station power supply: red and white
• 12V and 24V DC for the electronic circuits and relays: black, red and blue
• 12 V AC structures lighting: white and white
• 12 V AC turnout motors: orange and gray
• frog of the turnouts: plain green. NOTE: In the context of railroads, both real and model, the term frog refers to the point where two lines intersect. It may also be referred to as the common crossing, and Australians use the term V rail. If you are wondering how it got that name, it is because it resembles the frog of a horse's hoof.

Safety rules

There are also certain safety rules which you must obey at ALL times. Remember, you are working with electricity, which can cause severe shock or even death if you are not careful. We already mentioned keeping water away. Other precautions to be taken include the following:
• NEVER use a wire that is too small for its function. The higher the voltage, the greater the danger a wire poses. Voltage is the product of the amount of current that flows through the wire by the amount of resistance, which varies inversely with the size of the wire. If the voltage is too high there is the risk of overheating and an electrical fire can start.
• Make the best solders possible. A soldering iron with a wattage of forty to sixty should be ideal for the job. It should have two tips: a fine one for electronic circuits and a medium one for wiring. They should not be made of pure copper, which oxidizes easily; instead, there should be chromium, iron and nickel alloyed with the copper. They should also be clean and well-tinned. The soldering iron itself should be made of tin and lead in a ratio of 3:2.
• Never try to cool a soldering iron by breathing on it. That will only weaken the tool.
• Solder every piece of rail to either the next rail in the line or the DCC bus. The soldering should be done with a pair of stranded AWG22 wires or the equivalent. The rails themselves hold onto one another by mechanical means; therefore they should not be relied on to provide electrical conductivity.
• Choose the right connectors to be crimped or soldered. The crimping tool should also be carefully selected for the purpose and the size of the terminal adjusted to that of the wire. Terminals of the kind commonly used in automative wiring should be good for crimping.
• Thin the stranded wires that are fixed by the screws. This is not an option.
• Have a dry chemical fire extinguisher on hand. Unlike water, the contents of this type of extinguisher will work on an electrical fire.

The soldering process
1. Make sure that there is no oil, varnish or any other liquid on the rails.
2. Tin the rails and the wires.
3. Solder an AWG22 wire onto each rail, taking the polarity into account so as to avoid a short circuit. Also remember your color code described above.
4. Prepare the bus for installation by twisting it with a simple drill. Use a pair of 1½ mm wires.
5. Solder the AWG 22 wires, which should be cut as short as possible, to the bus of the concerned block from the rails.
6. Isolate the connections.