Gears of War 3 Game Guide

Act Three: Chapter 3 – Breakneck Run

Mow down Reavers that get in the way, and then get the three pipes up ahead.
Mow down the baby Corpsers and the ones that latch on. You can then hit a 
few explosive barrels, some Grubs, a few Reavers, and turret placements. You
will get stuck in sand and then get ready for incoming. Fend them off and 
you'll be home free.