Hello everybody. I was just wondering if anybody knew if they dynamic brake bug on Sand Patch Grade had been fixed yet? That is on some of the locos the dynamic brake effort goes down the faster you go. The complete opposite to how it is supposed to work. I know this only effected some of the locos, but it made down hill runs difficult with they dynamic brakes not working properly. Thanks in advance.
I was under the impression that the dynamic brakes are indeed supposed to decrease in effectiveness the faster you go. I believe they should be the strongest around the 25-35mph range, but if you're trying to stop your entire train when going 60mph, you won't get a crazy amount of help from the dynamics.
I did a full run on Sandpatch down to Cumberland today with the AC4400CW and the dynamic brakes worked exactly like this, as expected. They felt right to me. Cheers
For reference, here's a typical curve for real world dynamic brake force versus speed: DynamicBrakeForceVersusSpeed by Smokebox posted Jan 24, 2022 at 2:20 AM
Yes, this was talked about by Matt in (I think) the Sherman Hill stream. He suggested ignoring the higher speed limit and staying to 30 mph when cresting the rise and going downhill to maximize the dynamic brakes' effectiveness.
I believe that since that graph was published in 1954 (F7 era), electrical components have improved enough that the max effective point is reached around 30 mph. But the principle holds.
If your dyno's ain't gett'n it you may have to add a five lb set or so to assist. I know its not TSW2 but the application remains the same-