This unofficial trail starts from the meadow and the junction of the Pass Creek Trail and the Engineer Mountain Trail. While this is technically an unofficial trail, the area sees enough traffic that your way will be easy to discern. Rock cairns also mark the path. Take the switchbacking route to a nice viewpoint that some know as the Eagle's Nest. If you decide to keep going, you'll be scrambling and maybe using your hands on the way up. All in all, from the meadow you'll gain roughly 1300 feet in about .75 of a mile.
Good luck keeping your speed up in this section, the technical terrain will slow even the most experienced runners. While there is a trail, once you are actually on Engineer Mountain there is a fair bit of exposure and scrambling. Even though you are scrambling, Engineer sees enough traffic that a trail is visible on the way up. If you don't feel comfortable going on, it's okay! Stop, turn around, have a seat and enjoy the views. There isn't a bad seat in the house!