I'm just an observer and so far I lean to "DPU imperfection". You really dont know what your DPU's are going to do if the head-end halts immediately.
Or your DPU's hit a "dead spot" in communications. Have to think the dead spots will be identified and rectified. Sometimes identification will be after
a trainwreck. Passing this on to the members still working the throttle everyday.
There's one tunnel I run through about 3800 feet long, and while I rarely have DP on that line, when I do it will surely go no comm in there...but the tunnel is at the summit of my climb, albeit the still climbing side of said summit. When the DP's go out they are in 8 notch...so I just modulate my throttle to keep things sane. The signal will recover when the DP's are close to the end of the tunnel and I am just about ready for dynamics from every engine so it works out OK.
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I am not yet older than dirt...but I feel like it.