Wrong Side of the Tracks is the 16th stage, where Cash tries using the Subway to reach Starkweather, with the power cut off in order to try to trap Cash. It is a short stage, mostly using firearms.
Restoring power[edit]
When you enter the station, there are two officers in the main lobby. One will engage, while the other will flee into the side room. Exit the lobby by taking the door on the opposite side of the tracks, which allows you to flank an officer standing in the hall, and the officer that likewise was trying to flee. The end of the corridor leads to a locked door. Shoot the lock open, and exit to the tunnel.
Shortly after entering the tunnel, you will see a cutscene showing officers approaching from ahead, and those reinforcing from the street. If you want to advance, you'll need to sprint forward and take the right track to avoid the approaching enemies with their flashlights. If you want to fall back, there will be an enemy that intercepts you by the time you reach the door, but you can easily reach the corner of the corridor where you can easily attack the approaching swat members.
Your ultimate destination is at the end of the left-hand track. If you took the right-hand track previously, you will have to use various doors to return to the main track. The end of the track has a locked door that may be shot open, and only has two enemies in the room. Flip the switch. Return to the main station and enter the train.
If you haven't engaged the enemies that reinforced with the lobby, you'll encounter them on your way back to the train.
Exiting the station[edit]
After the save point and train, there is a dark room with two enemies patrolling. Quickly take cover and return fire. A third officer will approach from the stairs above. When you reach the stairs, some object will be thrown down, which you should evade. A fourth officer takes cover behind the counter in the middle of the room.
On the upper floor, first head to the right and take cover behind the bench to get a good position on the officers that approach through the gate. The flow will eventually stop. Head to the left, and pass through the gate, but take cover in the door on the right as there's still a few more officers waiting nearby.
The last stragglers simply wait behind cover, either the bench just before the stairs, and a stand in the middle of the stair.