Building a Subway

October 23, 2007

This post explains the movement of pieces and the creation of subway lines in Transantiago. It does not explain the scenes that occur as a result of these movements. That is a whole different issue.

Starting Positions

Each player selects one space on the board to be the station at which they start out (stations are represented by colored circles). Players each choose a name for these starting stations from a list of the actual station names of Santiago’s underground. Each player also has a uniquely colored pawn that represents the their location in the Santiago Metro (the colored dot).

Basic Movement: The First Round of Turns

Players can move their pawns, in a straight or angled line, anywhere on the board, creating a “subway line” that follows the trail of their pawn. Lines cannot normally “branch” into multiple alternate lines, but must take the form of a single curving thread or a loop, just like most subway lines in the world. Pawns only move station-to-station, however, so wherever they stop becomes a new station if it isn’t already one, complete with a name chosen off the list. In the first example, below, the blue player moves their pawn north and creates a new station.

Following this move, the red player, who goes next, moves their pawn south and east, creating a new station in the bottom right corner.

Finally, the yellow player, going third, moves their pawn west. The yellow player is not able to move their pawn across the newly formed Red Line of the Santiago Metro without first creating a “transfer station” where passengers can switch from the Yellow Line to the Red Line. So the yellow player creates a station where their lines intersect.

More Complex Movement: The Second Round of Turns

In the second round, the blue player begins by doing the same thing the yellow player did on their turn, connecting up to the Red Line by creating a transfer station. The blue player does this by moving south, bypassing the station they started from, and expanding the Blue Line all the way to the bottom row. Players, when moving pawns, can bypass any number of established stations, stopping wherever they like as long as it’s on the same line they started on.

The red player, moving second, connects the Red Line up to the Blue Line at the northernmost blue station. Notice that, because the red player lands on a previously established station, they don’t have to create a new station.

Finally, even more interestingly, the yellow player, already sitting on a transfer station, moves down the Red Line to join the blue player at the newly-built transfer station on the Red & Blue Lines. Players can travel on each other’s lines whenever they like, but can only travel on a new line if they begin their turn on a transfer station. This means, in a given turn, a player can only travel on a single subway line, though they are free to switch lines however they want between turns. However, note that players cannot establish stations on other players’ lines. They are limited to traveling between previously established stations.

Other Types of Movement: The Third Round of Turns

First, the blue player moves parallel to the Red Line for a few spaces, but ultimately connects up to the original station on the Yellow Line. Multiple lines can move in parallel without necessarily establishing transfer stations in every space.

Next, the red player turns the Red Line into a loop by connecting up to the original station on their line. However, the red player chooses to bypass that station, since the red pawn doesn’t have to stop there to create it, and continues down the Red Line to finally stop at the transfer station connecting to the Yellow Line.

Finally, the yellow player make a somewhat unusual move, connecting up with their original station in a manner that seems backwards, moving from a station that’s not on the Yellow Line to a Yellow Line station. This is only possible if, as in this case, the move would be legal going from the other direction, that is, it does not create a fork in the line but merely extends it.

I’m still less than totally convinced that I should include this kind of movement, since it’s not as intuitive as the other kinds and breaks the basic rule of “yellow player on Yellow Line can extend or build stations on the line; yellow player on other players lines is limited to what the other players have built.”

Forking

The only type of movement I didn’t show here is the rare type of movement that involves forking a line. I’m not sure at this point if 1) I should allow this, even though it is reasonably common for one or two lines of a subway system to fork, though Santiago doesn’t have any forking lines, or, 2) if I were to allow forking, how it would work.

Creating New Lines

This only happens if you add new players to a game already in progress. If players leave the game or are absent for one or more sessions, their subway line still stands, but cannot be extended. New stations can still be added to it, but only by other players connecting their lines to it.

2 Responses to “Building a Subway”

  1. eben Says:

    Mornington Crescent. I win!

  2. John Harper Says:

    This is super cool. I can’t wait to see how it links up with scene stuff.

    I’m not sure about yellow’s weird move, though. It seems to mess with the harmony. Maybe that won’t matter to the game play, though.


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