Dead Line

Dead Line, or Tutorial Standards, is an unused map that was originally designed to be the finale for the Dead Air campaign. When the finale for Dead Air was redesigned, the map was left in the game files to demonstrate as an example mini-campaign for mappers. It can still be accessed by typing map tutorial_standards into the developer console.

Starting in a small safe room, the Survivors must travel a short distance to reach an elevator and fight off a small Horde while waiting for it to lower. Taking the elevator to the other side of the station, the Survivors must radio for help and then hold out near a stationed minigun until a train arrives to carry them to safety.

The map is quite short but the cramped rooms will cause close-quarters combat to reign supreme and it is very easy for an unprepared team to be overwhelmed by sheer Infected numbers.

Campaign
The Survivor Bots will always grab the following weapons.
 * Nick will grab an SMG.
 * Ellis will grab a SMG.
 * Rochelle will grab an SMG.
 * Coach will grab a Pump Shotgun.

The safe room door opens to a small hallway that overlooks a small courtyard and the raised elevator. There will be a few Common Infected loitering about that are easy to dispose of. A flight of stairs leads up to the second floor, where the button to summon the elevator is on the wall next to three interconnected rooms. Before pressing the button be sure to locate a table containing an Assault Rifle, Auto Shotgun, Hunting Rifle, and an ammo pile. This table might spawn in any of the rooms.

Pressing the button starts the elevator lowering, but also summons the Horde (it is at this point that Special Infected are likely to start showing up). The easiest way to handle the Horde is simply to retreat back into the safe room, but the side room closest to the button is also relatively defensible, especially if the table with Tier 2 weapons spawned there.

Once the Horde is cleared out, take the elevator up as a team (a ladder will also retract up the wall in case anyone missed the elevator) onto a roof overlooking the cramped train station. The drop into the train station is one-way, so make sure to jump as a team to prevent a tardy player being snagged by a Smoker.

The train station itself has a table containing the radio that will summon the rescue. Beside the table is a First-Aid station containing four First-Aid kits and a weapons closet containing 4 Assault Rifles, Auto Shotguns, Hunting Rifles and pistols. To the east is a stationed Minigun which often has two gas cans sitting near the tracks. To the west is a rescue closet that often has two propane tanks, pipe bombs, and molotovs sitting outside of it. A fence prevents the Survivors from leaving further into the station, though Infected will spawn outside the fence. Infected can also spawn on a second floor overlooking the described area, but this floor is inaccessible to Survivors. The track itself is blocked by the train which will turn out to be the rescue vehicle.

Once the team has radioed for rescue, Infected will attack in waves from a wide arc of directions. Common Infected are supported by Specials including the usual two-Tank interludes, who often drop from the second floor. Once the second tank is killed, the train begins moving and its doors open, allowing the Survivors to board from the main platform. A closing cut scene then rolls showing the train leaving the station, after which the credits appear with the Dead Air logo superimposed.

The Survivors
Combat is almost exclusively at short-to-medium range, so it is recommended that Survivors emphasize shotguns and assault rifles in their loadouts. Due to the many chokepoints and narrow hallways, survivors should be very conscious of friendly-fire, especially if using shotguns. In general, there is no truly reliable location to make the team's last stand, as they all come with some very obvious downsides.

Closet Method
The rescue closet west of the train platform can provide a well-defensible space with only one entrance. Two Survivors with Shotguns can crouch in the doorway and focus on clearing crowds while the others stand behind them and lay down suppressing fire with Assault Rifles. Spitters are the most dangerous enemy to face in this closet so it is important to shoot her before she fires off her acid attack. The closet should of course be evacuated when Tanks arrive, whereupon the Survivors rely on using molotovs and heavy fire while dodging his attacks.

Minigun method
The minigun is facing the train platform and can completely cover an entire route of attack. The other three Survivors will have to focus on protecting the player manning the minigun as well as mopping up any Infected who attack from either the train tracks or the second floor. Players focusing on cover fire must always be checking above; Infected will drop right onto the minigun from the second floor, making friendly fire incredibly likely. The good news is that the area is relatively open allowing the team to spread out somewhat and keep an eye out for Special Infected.

Radio table method
The train station itself is a decent place to hold out because of the supplies. A first-aid station and weapons closet allows quick resupply and a decent view of the surrounding area. Note that it's possible to hide on top of the First-aid station by crouching, which makes that player immune to spitter attacks.

Versus
There is a Versus version of the map also included in Left 4 Dead 2, which can be accessed by typing map tutorial_standards_vs. It removes a few elements of randomness from the campaign version; the table with Tier 2 weapons in the area before the elevator always spawns in the same place and several isolated rooms (including the Rescue closet) are absent.