Now that we have the Spirit Train, it's time to set course for Whittleton, the village which is located on the lower left corner of the lowest track loop on the map. Use the stylus to draw a path along the tracks that you want the train to take in order to get there, then get the train in motion. Along the way to Whittleton, we'll not only have to deal with Moinks being on the track but also annoying Snurgles, flying creatures that like to swoop down on passing trains. Snurgles are very sensitive to loud noises, so give them a good blast of the train whistle to scare them away.
Once we stop at Whittleton, the first thing we want to do is get a shield. Go to the "triangular" house all the way to the southwest and talk to the merchant. He will sell you a shield for 80 rupees. You should have enough to buy a shield at this point.
Now go to the house on the north end of the village and talk to the chief. He will tell you there is a secret path to get to the Forest Sanctuary where the Forest Sage Gage lives. He will also warn you about the Lost Woods which will bring you back to where you started if you take a wrong turn.
You can talk to the other villagers who will give you clues as to how to get through the Lost Woods. Other than that, it's time to get ourselves going.
It's time to go through the Lost Woods in order to get to the Forest Sanctuary. Plot your course along the track that juts out to the west south of the upcoming junction and get the train rolling. Once we're in the Lost Woods, watch for four trees that will stick their branches toward the direction you should be going: if a tree branch points toward the right, push the track switch to the right; if it points toward the left, push the track switch to the left. Remember the clue "do not listen to the fourth tree": in the direction that its branch is pointing toward, push the track switch to the opposite direction. Note that with each tree you correctly pass by, the train will go faster, giving you less time to react to the next tree that comes along.
Successfully make it through the Lost Woods and you should arrive at the Forest Sanctuary station. To get to the sanctuary itself, we need to set off a Bomb Flower next to a switch orb to activate a bridge, then quickly carry another Bomb Flower across that bridge toward a series of blocks we need to blow up. Not making things any easier are Spinuts and Crows that like to come and take rupees from you. In another part of this area to the west, there are a group of head statues that we need to examine to see which ones are directly facing each other, then draw a line on a diagram that connects these two statues together. This will open a door into the sanctuary where we can talk to Gage, who will teach Link a Lokomo Song to play on the Spirit Flute as a duet in order to unlock more Spirit Tracks that lead to the Forest Temple. You may want to practice first on how to play the Spirit Flute before you actually perform the duet with Gage.
With the new tracks appearing, we can head back toward the train and head for the Forest Temple. On our way back to the train, there is a rocket-shaped statue that hums out a color-coded tune that we can learn to play with the Spirit Flute. This tune is the Song of Awakening, and if Link plays this tune around statues, they will awaken and give him valuable information.
Now that we're back on the train heading to the Forest Temple, there will be Skulltulas that will drop in front of us. Scare them away by using the train whistle.