1. BR406 Mg-brake seems to have wrong physics because it doesn't seem to increase brake force vs full brake (VB). Test stopping distance in VB from 160 km / h vs emergency (SB). Maybe the Mg-brake is only aesthetic?
2. RSN freight wagons (actually all wagons) are empty, even the trains are called "loaded". Take a loaded train in timetable and check the briefing (divide by number of wagons).
3. RSN passenger & freight wagons have incorrect braking physics (too strong brakes)
4. Trains with clasp brakes (klotzbremse) such as RSN freight wagons and Sand Patch grade wagons don't work like in reality.
Brake force vs speed should look something like this (x = speed (km / h), y = percentage of maximum brake force):
{
{x = 0, y = 1},
{x = 10, y = 0.743},
{x = 20, y = 0.600},
{x = 30, y = 0.506},
{x = 40, y = 0.451},
{x = 50, y = 0.414},
{x = 60, y = 0.394},
{x = 100, y = 0.331},
{x = 160, y = 0.286},
}
Or something similar to this (I took this from a curve I found in a study of block brakes), important thing is that it is * NOT * linear. In TSW2 it is linear = not realistic. It might seem like a small difference but it makes a huge difference for American freight trains when you are driving them down steep grades.
EDIT: For those who are skeptical of how much the difference in shape of friction curves can affect the simulation. Let me give an example of how trains are driven in mountain grades (1.5% or steeper or there abouts, someone might have the exact definition, I can't remember it).
In the USA they use "Tons per Operational Brake" (TOB) instead of BrH. It is defined as the train weight in tons divided by number of brake cylinders (usually one per car) so it basically is the average weight per car.
On the 2.4% grade at Tehachapi Pass the engineer will usually apply around 8-14 pounds depending on the TOB, this will nearly hold the speed steady but the engineer then uses dynamic brakes to fully control the speed. Usually the amount of air brakes applied is enough to hold the speed at 50% dynamic brakes at around 20-30mph.
Here is where the variable braking force with speed comes in: If the train has to stop, rather than applying more air the engineer simply increases the dynamic brakes to make the train decelerate, because the brakes are much more effective at low speed (due to the non-linear dependence) the train will stop even if the brakes were not enough to keep the speed constant at initial higher speed.
When the train has to move again, rather than releasing the brakes (this is not good because of how North American freight train brakes work, you could end up with a runaway train since the brakes wont have had time to fully recharge when the train has accelerated to the line speed again) the engineer throttles up enough to accelerate the train, then goes into dynamic braking close to the line speed and holds it there as before.
In TSW2 because of the unrealistic linear friction dependence, when you try to drive the train like this the train will never stop because the brake force hasn't increased enough at low speed to overcome the drop in brake force when the dynamic brakes fade away! This means that if you have to stop for a signal you have to increase the air brakes, but when you want to get moving again the brakes will be too strong back at line speed so you need to release them (no no) or use throttle going down hill! xD
and If you already have a working solution that would be much preferred than having to fix the .xml formatting.