It is undeniable that the creation of the GP (General Purpose) 7 changed railroading drastically. The GP7 units were designed by Dick Dilworth of EMD. His goal was to make a road switcher which would work well "out where the real work was being done." The design was based on observations from Alco and Baldwin Locomotives, as well as considerations of the needs of a freight train crew.

https://www.ign.com/videos/2009/04/07/half-life-2-video-half-life-2-whats-in-the-box

2021 update: It has been many years since I last went 'Foaming". I am keeping this post as is, but this isn't really a past-time I partake in any longer.