SubwayAnnouncer

The way the plugin works is you have place a command block around the rail and with a redstone triggering it. Then promt a command (which is on the bottom for reference) on the command block for the announcement to work and be triggered by the redstone.
Here are the command you're suppose to put:
Command 1: The Next Stop Announcement
Use this when the train is moving between stations to announce where it is heading.

The Syntax: /subwaybound <local|express> nextstop

Example: /subwaybound @a Manhattan A express nextstop Times Square

What it prints in chat: > this is a Manhattan bound A express train, the next stop is Times Square.

Command 2: The Current Stop Announcement
Use this when the train arrives at a station to announce the current stop and any available transfers.

The Syntax (Without Transfers): /this-stop

Example: /this-stop @a Times Square

What it prints in chat: > this is Times Square

The Syntax (With Transfers): /this-stop transfer <lines...>

Example: /this-stop @a Times Square transfer the N Q R W 1 2 3 and 7 trains

What it prints in chat: > this is Times Square, transfer is available to the N Q R W 1 2 3 and 7 trains