Definition & Meaning of "Mexican train"

What is "Mexican train"?

Mexican train is a popular domino game that is typically played by 2 to 8 players. The game is played with a set of double-12 dominoes, and each player starts by placing a tile on a central "train" that is shared by all players. Players take turns adding tiles to their own train or to the central train, matching the numbers on the ends of the dominoes. The objective is to be the first to play all of your tiles. One unique aspect of the game is the "Mexican train," a separate train that any player can add tiles to if they cannot play on their own. The game ends when a player runs out of tiles or no one can make a legal move, with the winner being the one with the fewest remaining tiles.