I'm almost certain Doom train = Phantom train. However considering some things I heard about in 1.0. I'm in agreement with the mine carts. Actually there, may have been a train of sorts running loads to and from the quarry/mines >Black Brush Station> The Royal Plantations. There's Nanawa Mines by the zone to north thanalan (yet there's no mining points there). A train tunnel going to an unknown area by the Rats Nest. Though most likely into the Copper Bell mines. The tracks to the north Might be into Cutters cry, Nanawa, or an area that was removed or never built (that waterway). Ul'dah was basically financed from all the mines, which drove commerce, and created the aristocracy and synicate. Currently they are financially strapped from Garliand 1.0, the mafia(syndicate) and refuges. Suggesting that the mines are no longer as productive thus no need for all the trains. Although it would be nice if we could take a train to and from sections in other areas, or into a dungeon.