Dynamic brakes have always been a bit messy in TSW, so they deserve a thread to cover their problems all on their own. And some excuse for me to ramble on and explain complicated things. Blower Noise: Dynamic brake noise should vary with dynamic brake current. It does not in TSW (so you hear the same noise from -0 amps to -1000 amps) Thing is, it used to. And it indeed should, as for those who don't know, dynamic brake noise comes from the dynamic brake fans/blowers, and the fans are mostly driven by the current generated from the motors. The higher the dynamic braking current, the faster the fans spin, (TSW does model that chain of events in fan animations) so the louder and higher pitch the noise becomes (which TSW does not model anymore). Motor excitation: As this is a technical post, prepare to get techincal! The diesel engine power actually increases with dynamic brake lever position, which might seem silly, but the engine here is not being used to power the motors, it is being used to power the magnets. It’s all about activating the electromagnets in the motors so the motors actually generate electricity. Without magnets, the motors won’t generate anything, and the power for the magnets must come from the engine, so that’s why you need an engine to use dynamic brakes...(As a note, it does not take that much power to get the electromagnets doing their thing, so even full dynamics really only requires around notch 3 engine power.) Anyway, this is not modelled in TSW (you could even get dynamic braking with the engine off! this is impossible in real life) In fact, this is almost never modelled at all. Some highly advanced sound/enhancement packs for TS18 are the only times I'd see this in a simulator, and it is only there for showing realistic RPM numbers (you could just dub in engine noise as an MSTS dev I know of did), it has no important effect. I think SimuGraph could handle that kind of complex thing, so why not? [I get the impression that the old SimuGraph motors are magic and have no differentiation between the field winding and armature winding. The new ones clearly do.] Power Lag: Due to the way dynamic brakes work in tandem with engine output, there is some delay between setting a dynamic brake position and the dynamic brakes reaching that resistance level as the engine power must increase to increase dynamics power, and that takes time (even after the dynamics have been set up). In TSW (and usually TS17 too, for that matter) once the dynamic brakes activated, they instantly jumped up to the setting provided, which is not really accurate, and also promotes being slam on-slam off with the dynamics. You could even lose points in TS17 from the jerk created by the dynamics slamming all the way on. Only a few locos would correctly model the smooth power up and power down, and that would require fancy LUA scripting. And then the evil we all know...physics: I don't know why...but TSW decided to split off from the typical dynamic brake physics systems which were tried, tested, and accepted in at least 5 other simulators. Now, I could not make a physically based argument for why dynamic brakes work the way they do, but I can safely say the other simulators got it right, and TSW is not right. The focus of motor physics in discussion has always been power, but braking was a more ignored side of the issue, so here goes: [TLDR: TSW does dynamic brake physics wrong, look to any other simulator to get a good idea of what should happen.] Dynamic brake vs dynamic brake position: The dynamic brake current should vary about linearly related to dynamic brake position: so notch 4 would give you around twice the current as notch 2 dynamics. But, as a lot would have noticed, in TSW, dynamic brake positions from setup-3 do almost nothing to the current, but when you hit 4-6, suddenly the current shoots up, then positions 7-8 don't do quite as much to the current. This makes the dynamics very hard to control and is not realistic at all. I graphed dynamic brake current as it relates to dynamic brake position (in "notches") at 70 mph in the AC4400CW, and both an exponential function and even a sine curve are a more accurate predictor of dynamic brake current than the linear relationship it should be. (I think the actual implementation is sigmoidal, now that I look at it.) Which is frankly absurd when a linear relationship is the truth. Dynamic brake vs speed: And the other thing that TSW decided to do differently was the dynamics current vs speed. It went for a strictly linear relationship: 0 mph means 0 dynamic current, 100 mph has 10x the dynamic current as 10 mph, etc. But in every other simulator, the dynamic current is actually direct for a bit, and then inverse, not totally direct: with 1. dynamics being most effective at slow speeds (25 mph or so [depends on loco]), not least effective as TSW suggests. 2. dynamics lose effectiveness when moving slower than that ideal speed, reaching 0 amps before a complete stop (speed depends on loco/traction motor type), while TSW only reaches 0 current when you are totally stopped-so that's definitely not realistic. And finally, 3. dynamics lose some effectiveness as speed increases. While in TSW, that linear relationship means current increases with speed. Up to completely insane numbers like -2000 amps, which should mean the resistors are on fire. You don't need to be an expert to know that's not right. There's no point in attaching a graph for TSW, that's just a line with a perfect correlation, but here's what one of those absurdly detailed "sound"/enhancement packs spits out at full dynamics on an SD70ACe: As I said, I couldn't tell you why that's not linear, as linear is nice and easy and sorta makes sense...but that's not how it is in real life. (As soon as you do stuff like field weakening and dynamic braking, stuff gets strangeeee) And as a simulator, TSW should do what happens in real life, not what makes sense. Yeah I know I wrote a lot, that's what physics problems do to you. And I didn't feel like it was enough to not explain this since dynamics are not in the UK/GWE so have not been in the focus and are not commonly used by a lot of people in the sim.