At the start of the game, once the players have received their Train cards and selected the Tickets they wish to keep, each player gets a Warehouse and 5 Depots of matching color. The Warehouse is placed in front of each player, with 4 Depots next to it. The 5th Depot is placed in any city on the board, starting with the player who will go last in the game, and the the second-to last and so on.
Each time a player uses his turn to draw train cards, he must first draw the top card off the train card deck and place it in any Warehouse without looking at it, before drawing his own Train cards. Each time a player uses his turn to claim a route into a city with a player's Depot in it (including their own), he may pick all the train cards from that player's Warehouse, by discarding one of his own Depots from his Warehouse back into the game box.
In addition to his regular turn, a player may always, as a free Action, take one or more Depots still next to his Warehouse and place them on any empty cities. At the end of the game, the player with the most unused Depots next to their Warehouse score 10 points. All tied players score the bonus. Once placed on the board, a Depot can never be moved nor removed, and may not co-exist with other pieces. And players may pick cards from 2 Warehouses in a single turn, when claiming a Route that connects 2 cities each with its own Depot, but they must still discard 2 of their own Depots. The number of Train cards stored in a Warehouse is open information. In the rare event there are no more Train Car cards left to draw or reshuffle and one or more players have run out of Depots, all Warehouses are immediately emptied out and the Train cards reshuffled into a new draw pile.
Depots can be played on any map.