3DZUG ICE 1 physics questions

I noticed that the weights for all the wagons ICE_WON1-14 are 75 tonnes, I thought they were closer to 50 tonnes (printed on the side of the wagon is 47t,48t and 60t for class 1, class 2 and Bistro).

Maybe this is for a reason and all the forces were scaled up (so that the acceleration/retardation is prototypical) so I did some acceleration tests.

From 0-100km/h, 0-200km/h and 0-250km/h it takes 1min30s, 4min0s and 6min41s respectively, while according to this website it takes 1min6s, 3min20s and 6min30s. Maybe the train is modelled after IGTBT convertors and the numbers on the page are with GTO converters (higher power) but it could also be explained by the weights being too high (and drag coefficient too low since the 0-250km/h timing is almost correct). Is this just an error or is there some reason behind the different weights?

I also noticed that the stopping distance is much shorter than real life. With full service (VB) the stopping distance from 160km/h in reality is 900-950m (I got this from drehscheibe-online), I measured 750m. I think this might be because the Mg + R bremsgewicht has been used rather than simply R. This gives realistic emergency brake (NB) distance but it will make the normal braking (step 1A-7) unrealistically high. If the mass-values were lowered to the real ones the electric brake will decelerate more but if the MaxBrakeforceByWeight was lowered a bit the stopping distance can be made to be realistic (900-950m) for normal use (no magnetic track brake simulation).

From S = vT/2 + v^2/2a, where a = retardation, T = 4s brake application time, you get

a(950m) = 1.15m/s^2

a(900m) = 1.22m/s^2

For comparison, the retardation in the sim is almost 1.5m/s^2 (!)

Alternatively you can script the full service (VB) to be lower than emergency and get both realistic VB-distance and realistic Mg+R distance.

I'm not 100% sure of all the numbers and maybe the websites were not correct so I wanted to ask this here before I mail support.

/William

Okay, I did some changes to the blueprint-files.

1. I changed the weight of the Tz to 80t (which is correct for GTO-converters)

2. I changed the weight of all the wagons to 57.4t to achieve 849t for the whole train (sources are so bad for this, wikipedia is unreliable as usual and says the difference between empty and loaded is over 100 tonnes (can't be right? :D), but I found an accident report for the Thun collision and some other sources that gave this number)

Change 1 + 2 gave 0-100km/h acceleration time of 1min10s (very close to the numbers i read) and 0-200km/h of 3min10s (slightly faster but that's because the drag value is too low or TS2020 being dumb)

3. Changed dynamic brake force so that it is 2 x 150 kN.

4. Changed deceleration values of Tz to 80 (from 130) and wagons to 135 (from 200). These numbers were based on the BrH for R-brake and then increased to achieve stopping distance of 900-950m from 160km/h (vs 750m before).

Change 1-2 means the Step 1A-2 will give higher deceleration due to E-brake force/weight and change 2-4 means you may need to apply more braking to achieve 0.5m/s^2 for LZB etc.

If anyone has some feedback for these numbers I would appreciate it, and as mentioned previously these changes might conflict with how the developers intended the scripting to work (for example max dynamic brake is 50% so the value has to be doubled in the sim-file vs reality) or maybe they are simply wrong (I doubt they are very wrong though).

Maybe I'm the only one that cares this much about the right values? xD

Awesome!