It's in Saffron city and in Goldenrod city.
You have to get the Magnet Train Pass from Copycat, who lives in the street below the Magnet Train Station in Saffron City.Her house has a roof that looks like a LEGO. Find her Clefairy Doll, which is in the Pokemon Lovers Club in Vermillion City, and talk to the man next to it, who will then give it to you. Return it to her to get a train pass.
after you get the magnet train pass use the magnet train
You give it back & she will give you the magnet train pass.
you have to get into kanto first than once you get the magnet train pass there should be a guy that will give you a device that will show you where latias is.
Train
If you mean the magnet train it's in saffron city and goldenrod city.
You have to help the CopyCat girl in the Pink House in Saffron City with her problem (after you defeat Red). After completing her task, she'll give you the train pass. You can then go on the magnet train.
Trade your Electabuzz holding a magnet.
You must "endlessly" train your Pokemon.
go to magnet train manger and ask him to give you a train pass
you can ride the magnet train
You can use it to take the magnet train to kanto I think.
After you have beaten red, go to professor oak. get a kanto starter. use the magnet train or fly to jhoto. go to Mr. Pokemon's house and he will give you the red orb