STORY MISSION 17 - Find 4Kim
Rewards: $2500, 4000 Overcharge, Senor Freeze Trap
Go to the Hepcat's Diner
Leave the rubble strewn wreckage of the Hot Dog Factory and head for the marker on the map. Listen to Norton digging himself deeper as you go. When you arrive, you'll see Sam offering himself up on a platter. Or at least standing on one.
Go and find 4Kim at the train station
Look above the skyline nearby to see the huge rail and building above everything else. This is the train station and you need to reach it. But before that, we'll head for the station on the ground under it. When you arrive, you'll see that scabs are infesting the area. Pull out your dirty harry and start clearing the path. The scabs have also started building turrets, these can easily be taken down with a shot or two, but they add more projectiles to the firefight, so keep an eye out.
Meet 4Kim on the station platform
Jump the barrier when the roller doors open and immediately look left for some ammo crates. Cross to the building opposite and start bouncing your way up to the platform above (shooting scabs on the way if you like). When you land on the platform, you'll see 4Kim being hustled into a train car and the chase will begin.
This chase sequence is timed (despite the lack of a timer on screen). You need to follow the train along the rails, making detours whenever the track is destroyed. You'll also need to dodge the constant stream of mines dropped on the rails as well. Keep an eye out for ammo crates to melee as you grind if you're running low.
You need to shoot the thrusters at the rear of the train multiple times until the final car's thrusters are destroyed. A single well aimed shot from the dirty harry will take out a thruster, so use it to destroy them. Ignore any enemies on the way as the train should be your only concern during this sequence. Once the train grinds to a halt, watch the scene and the level will finish.