The majority of toy trains run on low voltage DC (direct current), which is different from the AC (alternating current) running through your home's power outlets. Because of this difference a toy train needs a transformer to convert the AC from your home into the DC it requires for operation. Wiring this transformer to the track of your toy train properly is essential to the train's operation. Fortunately, most toy trains require only a two-wire hookup that can be quickly setup and have the operational in less than 5 minutes.
Make sure the transformer is unplugged from your wall before you create the connection.
Place the transformer where you intend to operate it from and measure the distance from the transformer to the nearest track for your toy train.
Cut a pair of wires to the measured length plus one inch. Strip the ends of the wires using the wire strippers, revealing about ¼ inch of the metal inside the wire insulators.
Locate the lockon, which is a small flat rectangle containing four metal tabs for three railed tracks, two small ones at one edge with a hoop attached, one longer one in the middle, and a small tab centered at the other edge, and place it flat on a surface with the tabs facing up. Press the tabs containing the loop downward so that the loop is exposed, and slip an end of a wire into the loop, bending the wire back towards the insulated end around the loop. Repeat the process with the second loop and the other wire. Two tracked toy trains, such as HO scaled models, often have the two wires pre-connected to the track and do not require the lockon.
Connect the lockon to the track by slipping the center tab under the nearest edge of the rail, nearest the transformer. With the rail edge beneath the tab, slip the far centered tab beneath the center rail, pressing upward to clip the lockon into place.
Connect the other ends of the wires to the transformer, one each to the screw located on the transformer marked, "to track". Unscrew the screw and then bend the exposed end of the wire around the screw. Tighten the screw to secure the wire in place.