[PC - Steam] I just reran service N542 - Coal - Rockwood to Cumberland (12:30) from the AC4400CW timetable and had a sudden derailment at roughly the same place as before, soon after the Sand Patch checkpoint & tunnel and about 12 miles from Hyndman. Dynamic brakes were at about 50%; no air or loco brakes engaged; speed was around 22 or 23 mph; no wheel slippage, lurching, or other warning of any kind--everything was going perfectly smoothly.
Can confirm the same location on a different service, Q226 Autorack Louisville-Baltimore (13:58). Right outside the tunnel with an AC4400 and SD40-2 in the lead, dynamics at 100%, train brake at minimum application. Heading about 29 MPH with no wheelslip and derailed at the same spot as original post.
I also had an AC4400 lead and SD40-2 follower but forgot to mention it in my post. Thanks for the reminder! Don't know if the pairing is important, or just the AC4400 lead, or neither, but every bit of info helps.
We've got an internal report of crashes when using the dynamic brake logged for SPG, no work has been made on it yet but it is a high priority.
