When Zelda asks you which realm to go to, say to go to the Snow Realm since she saw that it's connected to the Fire Realm. Use the tracks that go east to get into the Fire Realm.
Set your course for the large structure with multiple doors in the middle of the map. If you try going to the small cave (Targeting Range) instead, you'll be told that it's closed, so don't bother with it.
As you head into the Fire Realm, the volcano starts erupting. If any rocks fall onto the tracks, break them apart with the cannon.
On your way to the city, you'll go through a tunnel. Be sure to slow down just as you approach the exit of the tunnel, because the platform is right on the other side.
The path to the village has been blocked because of the volcano's eruptions. A villager near the lava spout says to climb up the mountain to visit Kagoron, who is praying at the altar. Go west and up the stairs to start working your way up.
Climb the Mountain
Walk up the stairs near the postbox and walk past the piles of iron to find a treasure chest that contains a random treasure. Go back down and walk to the left.
Watch the timing of the boulders to see how to get past them without getting hit. You will need to hide out in the bends of the path to keep from getting hit. You will also have to avoid the falling rocks of fire. This part is all about timing and about hiding in the bends of the path. Use the roll attack by tapping twice if you don't seem to be able to go quickly enough.
Eventually you will reach a grassy area with a crystal switch. There are two whip poles to the left, and when you hit the switch, a bridge temporarily appears. You will need to whip across and then get across the bridge before it disappears.
To do this, place a bomb next to the switch, but don't throw the bomb directly at it. Walk toward the whip poles, but don't let the crystal switch go off screen. You need to wait until the bomb explodes and activates the switch, and then you can whip across and use the roll attack to get across the bridge before it disappears.
Exit north for now. You can use the shortcut down the mountain in a moment. You will meet with Kagoron. He will tell you to go back to town and get your train ready.
Use the south exit, then go to the right to use the shortcut down the mountain. Whip across, then open the chest here to get a random treasure item.
When you go south, there will be several places where you can hop down, but you can get a random treasure item if you hop down onto the ledge in the middle of the map that points downward. Then return to the Goron Village.
When you walk near the large Goron near the train platform, Kagoron will show up and get the large Goron to help add a freight car to your train. Kagoron asks you to go get something that is cold enough to get rid of the lava.
Go west to the Snow Realm and visit the Anouki Village. The guy near the entrance will ask you to bring some lumber and a handyman. If you wait a moment, Honcho will come up to you and ask if you need something. He'll point out the place on the map where a guy sells Mega Ice. It's on the left side, south of the small pond. The guy there asks you to take him to a clear pool of water. He means Wellspring Station, where Ferrus's house is. Agree to take him.
Before you leave the Anouki Village, use your boomerang to freeze the water with the torch to the left of the water to get access to the treasure chest in the corner, which contains a random treasure, then go get into your train and ride over to Wellspring Station.
The Anouki will walk onto the pier to the left of Ferrus's house. Before talking to him, use your boomerang to freeze the water and get access to the stamp station in the back wall.
Then talk to the Anouki. You'll receive a Force Gem. He'll say to come back later to get the Mega Ice. Just go into Ferrus's house and back out again, and the Mega Ice will be ready. He'll want to charge 25 rupees, but you can actually just keep saying it's too expensive, and the guy will give it to you for free.
With the Mega Ice in your freight car, go back to the Goron Village. You will have to avoid getting hit by enemies. Also, there is a Dark Train hanging out in front of the Targeting Range, so you have to go the long way around to the village using the winding north path. Keep an eye on the paths of the Dark Trains and adjust your course to make sure to avoid them.
Once you are back in the Goron Village, run over to the left side where you went up the mountain before and you will find Kagoron standing there. Tell him that you have the ice. You need at least ten pieces of ice.
You can go back to the huts in the back of the village now. There is a treasure that you can reach if you go up onto the hill behind the three houses that make a triangle on the map. Walk across the bridge to the left to find the treasure.
You can go in and talk to all of the Gorons if you want. One of the Gorons is outside, unable to reach his house because the lava is still there. He asks you to bring more ice, which you can do if you want, or just come back later and do it.
Go talk to the Elder in the biggest house up north. He will agree to open the path to you. Go through the door that he walked away from.
Cave to the Sanctuary
Use your boomerang on the Fire Keese that are in your way, then head to the upper-left part of the cave where there is a whip pole. Whip across, then step on the switch to extend two permanent bridges. Cross them, then avoid the shaking pots that contain Like-Likes. If one comes out, throw a couple of bombs at it for the most hands-free way to kill it.
Before going up the stairs to the next floor, walk left from the ledge just above where you encountered the Like-Likes. There is a treasure chest here that contains a random treasure item. Go back and go up the stairs to the next floor.
In the outside area, you will have to fight more Fire Keese and avoid more falling lava rocks. There are also some chomping plants. You can kill those with a bomb flower, or just use the boomerang to cut the stem, then use the sword to kill the head. Be careful, because they spew fireballs at you.
Use your boomerang to light all of the torches to create three bridges. You'll create one bridge after lighting the first set of torches, then you can go down lower and light two torches there to create two more bridges.
Go across the lower-left bridge first to find a treasure in the upper left corner of the map. Then cross the topmost bridge to find the stamp station.
From the stamp station, you can hop down from the southern edge of the ledge to reach the area across the middle bridge. Go right and you will find a stone head puzzle. The lava rocks will stop falling in this area.
The sign in this area tells a story. This is a hint for figuring out how to unlock the door. It says that the light of friendship shone between the men, so you have to figure out which two statues represent the two men and play the Song of Light between them. The popular man is the one that most of the other statues are looking at. That's the one in the center. He is looking at the woman he loves, at the top middle. The woman only has eyes for the other man, who is at the middle right. So stand between the center statue and the middle right statue and play the Song of Light. The door will unlock, so go through.
Duet with Embrose
You will find Embrose. Play the duet with him to restore the tracks to the Fire Temple. Afterward, he'll tell you to talk to the people of the Goron Village before you head to the Fire Temple.