Left 4 Dead Wiki
L4d bh bridge.jpg
Chapter 3
The Bridge
Campaign Blood Harvest
Blood Harvest Chapter Chronology
Chapter 2
The Tunnel
Chapter 3
The Bridge
Chapter 4
The Train Station
"You know, I bet we can knock that bridge down."

The Bridge is the third chapter of the fifth campaign, Blood Harvest.

The Survivors exit the railroad tunnel and re-enter the forest. They follow a pathway through a gully up to a service building connected to an extension of the railroad tunnel. By entering this building and descending a flight of stairs, the Survivors are able to re-join the tracks in the open air once again.

Leaving the tunnel behind for good, they follow the railway past an engine shed until they encounter a signal gantry and bridge connected to high ground on their left. Francis' suggestion that the bridge be knocked down to continue on their way is agreed to. The Survivors check out a service building on the left for supplies and release the brake on a train car to drop the bridge. Unfortunately this triggers a Crescendo Event during which time the Survivors face an Infected attack from no less than three directions.

After defeating the Infected hordes, the Survivors climb the fallen bridge to reach high ground. They briefly head back into the forest before entering a small cabin serving as the ending safe room.


Also see: Tactics

All campaign walkthroughs are done on Normal difficulty in single player, and are meant to give tips on what to do and generally point out things that might otherwise be missed.

There are, of course, a few key things to always remember:

  • Stop, look, and listen.
    • Being observant might alert you to something nasty ahead of time, like a Witch, Special Infected or Tank, and allow you to prepare yourself.
  • Teamwork.
    • This cannot be stressed enough. Left 4 Dead is supposed to be a cooperative game. Communicate with your teammates, if you're playing with others, or if you're by yourself with the AI, point out things they might otherwise miss. In all cases, watch out for each other and take care of each other. You are not going to survive the zombie apocalypse by yourself.
  • Be ready for anything.
  • Don't panic.

These woods are as thick as ever. Find the train tracks again, as quick as you can, and continue onwards where rescue is waiting.


The Bridge Map

When starting from this chapter, the AI Survivors will grab:

When the Tier 2 weapons are found, they will grab:

Otherwise, they will keep the weapons they had in the last chapter. (See The Tunnel for a list of weapons they will grab there.)

First off, snatch up some ammo, patch yourself up and move out. If you want, you can even change your weapon, but if you have not started from here, you will probably have a Tier 2 weapon. Grab what you can, and head on out.

The direct approach would be to turn left and head towards the end of the passage. Then turn right and go straight towards the red light. Otherwise, turn right to take a route that will take you past a generator room containing pills, Molotovs, or Pipe bombs. Which ever way you take, keep an eye out for gas cans and propane tanks. Collect these and bring them with you.

Once you've reached the red light, take the doorway on the left and make another left at the end of the passage. A propane tank and gas can usually be found in this passage. In front, you will now see the open air. Common Infected will be loitering outside in front and above you on the tunnel abutments. At the same time, a hurry-up horde is very likely to attack you from the passage to your rear. A suggestion is to throw a gas can or propane bottle out of the tunnel mouth and so help clear the way.

Exit the tunnel and turn 180 degrees to snipe the Infected above you. Note that this is a good place for a Smoker to put in an appearance on one of the ridges above whilst a Witch may well also be present on the path before you. Worst case, a Tank will spawn soon after you have left the tunnel complex and fighting him in what is otherwise a relatively tight space is somewhat challenging: expect at least one team member to be incapacitated during the fight.

Head on up the clearly defined pathway. Just before it turns hard right and up-hill, check into a small recessed area to the left since supplies such as pills or a throwable may be found here. Be ready for a horde attack storming down from the bluffs above at this point. Towards the top of the rise, a large number of loitering Common Infected will be encountered ahead of you and off to the right: snipe them to clear the way.

Coming into view on your left is a building window and door recessed into the hillside: this is your next goal. Approach the building, smash the window or invade the door and clean out any Infected inside. Note that a hurry-up horde may spawn within seconds of arriving at this structure. If so, this is a tricky one to fight as they jump down on you from above as part of their attack. The best thing is to get inside the building and force them into chokepoints formed by the door and window. A rack next to the door may contain supplies.

A steep flight of stairs leads down into the building. At the base, a table often provides Tier 2 weapons along with a chance of pills or an extra Pistol. Grab what you can, and continue. Follow the passageways, noting the chance to snag a gas can or propane tank until you see in front of you a doorway framing what is obviously a railroad wagon. Approach the doorway and clean out any nearby Infected. You will notice yet another table outside the door that may give up Tier 2 weapons.

It is from this point that you need to start planning how you want to get through the up-coming Crescendo Event. A suggestion is to hold onto any gas cans or propane tanks you have in your possession since these will be good force multipliers during the finale.

Exiting the tunnel for the final time, you find yourself in a wide railroad cutting containing a signal gantry, bridge, stalled wagons, an engine shed and signal hut containing a back-up electricity generator. This space is densely populated with easily agitated Common Infected. Lighting is bad and the risk of a sneak attack is thus quite high.

Since the Survivors are probably getting low on ammo, a good idea is to duck into the engine shed on the right where an ammo pile will be found and a bonus may be an extra gas can or propane tank together with pills and throwables. If present, take these explosives with you; repeatedly throwing them ahead and going back for the others of playing Solo or with a couple of bots. The plan is to bring as many explosive items with you to the scene of the finale as you can manage.

Proceed further down the tracks and you will see the aforementioned signal hut to the left. Go inside and check for equipment. This building has a medical cabinet and very often an ammo stash. Less commonly but not a rare find are Tier 2 weapons as well. Directly opposite this hut is a solitary railroad wagon with ladder on the side. Climbing up will reveal a supply of Molotovs: take note of this.

Now is the time to finalize the plan for the Crescendo Event. The basic sequence is the release of a train wagon will drop the bridge and set off the event. Attackers will come from three directions: from both sides of the cutting and from right. Once you settled on your plan, proceed up the tracks away from the bridge until you reach a railroad wagon with a yellow brake handle on the side. Releasing the brake sets the wagon on motion, it knocks down the bridge and starts the finale. Note that in the area behind this wagon is a relatively large group of Common Infected which you may wish to cull with Pistols before touching the wagon brake.

There are several ways to handle the finale Crescendo Event:

  1. Position the team inside the cabin with the ammo and the first aid cabinet. Then send two Survivors out to detach the train car. One Survivor is there to detach it and the other is there to cover the first Survivor. The Survivors can generally fight from the main room with supplies, covering the two windows and two doors.
  2. The second approach is similar to the last in that the Survivors will be positioned inside the cabin, but will be inside the cabin's bathroom. Once the two Survivors have returned to the bathroom after summoning the horde, the four Survivors can adopt the classic "closet-position". This consists of two Survivors ducked in front and either using melee or shooting and two Survivors standing behind them and firing over them. Preferably, anyone with a shotgun should be one of the two ducked in front.
  3. The third option is to call the horde and retreat back to the small barn-like structure with ammunition. The downside to this tactic is that the horde can quickly catch up to you before you've reached the barn. The upside to it is that you'll never need to worry about ammunition and you have a somewhat large choke point.
  4. A fourth option is to pre-position a covering team on the roof of the isolated wagon with the Molotovs on the roof. Setting out any gas cans or propane tanks that you have brought along with you will put the odds in your favor. Once the brake is released, sprint and join the team on the wagon roof. Beat off the horde as they try to climb the sides of the wagon. It is close-range combat and with each team member covering a side, relatively easy fighting (but always keep an eye out for the odd Smoker). Fire the gas cans and propane tanks as needed and rain down Molotovs to help things along. Keep a pipe bomb or two in reserve for distraction purposes once you decide things have quieted down for the sprint to the bridge. Toss a pipe bomb then go hard for the bridge. Locate a covering fireteam on the bridge to allow the last team member to disengage safely. Sprint hard for the safe house once contact is broken whilst staying alert since a Tank occasionally spawns near the safe room.
  5. The final method is to run for the safe room without bothering too much about the hordes. Whilst this is never recommended as a standard procedure, it can however work quite well with this level. First, make sure someone has a Pipe bomb. Then clear out the rough area around where the bridge will fall and send some Survivors to activate the train car. Wait near where the bridge will collapse, and once it does, have each Survivor toss their Pipe bomb and sprint hard up the bridge for the safe room. The key word is run!

Unless you've used the fifth method, once the horde has been suppressed, make your way back to the bridge. The rolling wagon will have knocked down the bridge, allowing you to climb it to the ridge overlooking the railway area. Clear out any Infected up here and keep moving past the broken fence. Just keep moving and soon, you'll see the safe room in the cabin to your left. Close the door and take a breather! Now get ready, your train is waiting for you at The Train Station!

Left 4 Dead 2 Version[]

The L4D2 version received an update to the train layout that transforms the ending into a crescendo event of endless zombies in addition to the panic event normally created by activating the train in L4D1. To avoid being overwhelmed, from the moment the bridge collapses players should lose no time in moving towards the safe room. The safe room area had additional fences placed in to give out of sight places for Infected to emerge from right up to the very end.


The Survivors[]

With humans controlling the Special Infected, things can only get harder. However, they can't spawn until you leave the safe room. That doesn't mean that you should let them have a good chance to find just the right spot, though! Hurry up and get your supplies, and get running!

Unfortunately, this level can be disastrous for you and your teammates. As soon as you exit the safe room, there is an all-too-common Tank spawn location. From experience, anyone would know that a Tank in close quarters such as these is not to be trifled with. Many teams have barely left the safe room only to be crushed by such a giant. Stay sharp!

If you are lucky, when you exit into the woods, you'll have a fairly quick and painless journey through. However, a competent team of Infected can easily set up horrible ambushes as you exit. Boomers can rain down vomit on their enemies, Smokers can drag Survivors long distances with little chance of being shot and Hunters can score a nice amount of instant pounce damage. Of course, a Tank or Witch is also a lot of trouble here.

The next major concern in the level is the crescendo event. As with most, if the Survivor team is lacking and the Infected team is excelling, they'll have little trouble finishing you all off. You need to anticipate their attacks and try to counter them. Another thing to be warned of is if you and your team find no Special Infected attacking you during the event. This generally means that they are preparing for a potentially fatal ambush. Stay on your guard.

When you see the safe room and you know you're almost there, make sure you are with your teammates before you make a dash for it. If you make a break for it alone, it is not unlikely that a Hunter will be waiting for your arrival and possibly kill you before the others can reach you. No one can survive the infection alone. Teamwork is essential.

The Infected[]

See also: The Boomer, The Hunter, The Smoker, The Tank

Though they might be immune to the Infection, they aren't immune to death; no one is. Work together to make sure they're victims of this rampant virus, one way or another.

Overall Tips

  • Any survivors that choose to run ahead of or fall behind their teammates will be much easier to seriously damage and kill. The farther away they are from their teammates, the more likely they are to be incapacitated or die before their teammates can reach them.
  • The Survivors all have outlines around them, showing their status and location. Green means they're healthy. Yellow means they're hurt. Red means they're low on health. Purple means they've been covered in Boomer bile. You can probably discern which to seek out first if possible.
  • Think like a Survivor. When you play as one, when are the worst times that something could come at you? Exploit that knowledge.
  • Teamwork, as aforementioned. Has a Boomer gotten their bile all over the Survivors? Jump one of them or a clean one. They can't see their teammates' aura until they're clean...and by then, it might be too late.
  • As much as teamwork is a strength for you and your enemies, a lack of it will be their downfall. If you can focus all of your energy on killing one of the Survivors, the rest will be that much easier to take down. Not only will they have one less gun, but they will have three Survivors to your three incapacitating Infected.

Boomers: The various tight spaces and open areas are a great combination for you. Not only can you hide in side rooms in the tight corridors and spew vomit as the Survivors pass, but you can also use height to your advantage in wide-open areas. From there, you can rain your bile down and on top of the Survivors. Try not to get killed in this one, as it is often difficult to relocate yourself to an adequately effective position. If you can cover the Survivors while other Infected are in position, Smokers and Hunters can use the opportunity you created to put the hurt on the Survivors. There's a Witch? Conceal her! Odds are that one genius Survivor is going to shoot you and the Witch in one go.

Hunters: This level can work to your advantage. It is fairly straightforward to find a high location, wait, and pounce when the Survivors approach, causing some instant damage. It's a rule of thumb to see your prey before they see you so you can literally get the drop on them. Hunters work best in ambush situations. It is not advised to attack a group unless you're trying to distract them, or simply scare them. Try to hide in small spaces, though. This level has a fair amount of side passages and rooms for you to lurk in. Pounce people who wander off. Always remember that you have a strong melee attack, so if you can't quite pounce, feel entirely free to melee.

Smokers: The several outdoor locations are excellent for you to set up dangerous ambushes and catch the Survivors off-guard. Remember that if there are high locations you can reach, there is no point in moving down and attacking the Survivors up close; this is a suicide run. Instead, exploit these heights and attack from there. If you've angled your attack perfectly, you won't be seen properly by the Survivors and they won't be able to kill you. Although close quarters are not good for you, if you find yourself trapped by Survivors, don't just sit still and let them kill you. Lash out at them! Use your powerful secondary melee attack! If they are hurt enough, they may even be incapacitated, which can save your life!

Tanks: These interiors are golden locations for you to arrive on the scene. If you are unlucky and spawn outside, you can still hurl things such as tree trunks into the Survivors! Even outside, you can single-handedly end the game. Your rock throw is usually very underestimated. With practice, it can be devastating and deal a lot of damage to the group of Survivors quickly. As a rule of thumb, aim your reticule above, and perhaps ahead of, the target while throwing. Attack with precision and force; don't let the Survivors get any further!


See also: Survival Mode

The Survivors tried to knock down the bridge and continue onwards effortlessly. But their plan failed, and now the Infected are out for blood. How long can the Survivors hold out?

Overall Tips

  • Teamwork is essential to long-term survival.
  • In this mode, most of the popular choke points, closets and easily defensible corners are removed. Even if you find one that has not been removed, it is not recommended that you fight from there as The Tank will quickly defeat you when he arrives.
  • You have an infinite amount of time to prepare. Use this to your advantage. Take as much time as you can to set up gas cans, propane tanks, oxygen tanks and to find a good place to fight from.
  • When searching for a place to fight from, remember that you need a location that not only limits where the horde attacks from, but also gives you a fair chance against the Tank. You either need to be able to fall back and deal with the Tank easily, or have a good enough vantage point to kill him before he can get too close.
  • Ammunition is a problem. Unless you are being overrun with Infected or fighting a Tank, try to use your pistols as much as possible. Conserving ammunition should be a priority, as trying to get more during a horde attack can often be fatal. When you do head out for ammunition, remember to take at least one teammate with you.

Cabin Method

Position the team inside the cabin with the ammo and the first aid cabinet. Then send one Survivor out to detach the train car. The Survivors can generally fight from the main room with supplies, covering the two windows and two doors. Generally, this means Smokers and Hunters are more or less not a problem. Boomers, however, are still a concern and the Survivors should remain vigilant for them. When the Tank shows up to the party, the Survivors can exit through either entrance and fight him on open ground. Do it quickly, though! You don't want the horde to reappear whilst you're outside battling a Tank! Once he's dead, return to the cabin and repeat.

Boxcar Method

You can simply guard the top of a boxcar. There are Molotovs on top of one and the Infected have to climb up the ladder and the sides, making them easy targets. Your primary concern with this method is the Smoker. If the Smoker manages to tug a Survivor over the edge during a horde attack, they're almost guaranteed to die. Also, to a lesser extent, Hunters can produce the same effect by pouncing someone on the boxcar and stumbling the others over the edge. The Tank is dealt easily with this method as he can be seen long before he can get in close. With concentrated fire, he should go down, no problem.

Out Of Map

There is a way to get out of the map. What you have to do is go to where the boxcar is (the one where you can get on to the bridge), and go behind it and preferably have a propane tank with you. What you do is go by the wall and keep walking sideways into it while moving forward and crouching repeatably. If done correctly, you should glitch into the other side of the mountain. If you can only get halfway into the wall, put down the propane tank and shoot it. It will hopefully result in you being pushed outside the map. While under the map, you can start the horde, but its better to have someone else do it because if you do, you risk being teleported back up to the map. This works on the 360 and sometimes on the PC.


  • When starting the Crescendo Event, the train car detaches from the one behind it. But if you notice, the link hand phases through the hand of the car behind it.
  • There is a way to get on the bridge without breaking it. From the red container with two yellow ladders, you can jump on the mountains on the side of the tracks. Eventually, if you keep walking on those mountains, you will reach the wooden bridge. Be careful, because at the middle of this bridge, the ground is not solid and you will fall to your death.
  • When you're standing under the bridge as a Survivor, and the bridge falls down on you, you won't take any damage, even though it can kill a Tank.
  • On rare occasions, if a Witch spawns on the bridge, the only thing you have to do is knock it down and the Witch will be killed instantly.
  • The bridge over the tracks has semaphore signals, almost all of these have been removed from use in the United States.
  • The Bridge shares the same name as the finale of Left 4 Dead 2's The Parish, The Bridge.
Left 4 Dead Left 4 Dead 2
L4d no mercy.jpg
No Mercy
The Apartments / The Subway / The Sewer / The Hospital / Rooftop Finale Price chopper.jpg
Dead Center
The Hotel / The Streets / The Mall / The Atrium
L4d achievement survive garage.png
Crash Course
The Alleys / The Truck Depot Finale Torch-Bearer.gif
The Passing
The Riverbank / The Underground / The Port
L4d death toll.jpg
Death Toll
The Turnpike / The Drains / The Church / The Town / Boathouse Finale Midnight rider.jpg
Dark Carnival
The Highway / The Fairgrounds / The Coaster / The Barns / The Concert
L4d dead air.jpg
Dead Air
The Greenhouse / The Crane / The Construction Site / The Terminal / Runway Finale Ragin cajun.jpg
Swamp Fever
Plank Country / The Swamp / Shanty Town / The Plantation
L4d blood harvest.jpg
Blood Harvest
The Woods / The Tunnel / The Bridge / The Train Station / Farmhouse Finale Weatherman.jpg
Hard Rain
The Milltown / The Sugar Mill / Mill Escape / Return To Town / Town Escape
Supreme sacrifice.png
The Sacrifice
The Docks / The Barge / Port Finale Bridge burner.jpg
The Parish
The Waterfront / The Park / The Cemetery / The Quarter / The Bridge
L4D last stand.jpg
The Last Stand
The Lighthouse Streamcrosser.jpg
Cold Stream
Alpine Creek / South Pine Stream / Memorial Bridge / Cut-throat Creek
L4d outbreak.jpg
Dam It
Orchard / Campground / Dam Achievement Still Standing.png
The Last Stand
The Junkyard / Lighthouse Finale