The region connects to forlorn muskeg at one end of the rail line. You want to go under the fallen tree that leads to the Yard. In the Broken Railroad, head to the frozen lake. You'll find the body leaning beside the train car, on the Broken Railroad end of the Muskeg. Broken Railroad Cache This cache is unlocked by finding the bloody note next to the body in Forlorn Muskeg.
