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Author Topic: IET trains does not have the correct acceleration rate and livery variants  (Read 9850 times)

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Offline jamespetts

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Re: IET trains does not have the same acceleration rate and livery variants
« Reply #70 on: April 06, 2019, 10:32:17 PM »
About the acceleration rate thing, did you say that you wanted the acceleration rate in horsepower, because I found the horsepower for the class 800s on wiki. and the horsepower is 750 (560 kW) per engine (for I assume diesel).

The power is easy to find - it is the tractive effort that governs acceleration and that is hard to find (as discussed extensively above).

Offline thegamer7893

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The power is easy to find - it is the tractive effort that governs acceleration and that is hard to find (as discussed extensively above).

James, how did you find the tractive effort for the other trains in Simutrans?

Offline jamespetts

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James, how did you find the tractive effort for the other trains in Simutrans?

If they were not available on Wikipedia or another source, I had to guess based on extrapolating from other locomotives or multiple units whose tractive effort is known.

Generally, it is easy to find the tractive effort of locomotives, but difficult to find the tractive effort of multiple units. I believe that I did manage to find somewhere the tractive effort for some of the "Desiro" series of multiple units (the class 450, etc.), but I could not find it for many other units, and had to extrapolate many of the other modern units from this.

Offline thegamer7893

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Re: IET trains does not have the correct acceleration rate and livery variants
« Reply #73 on: September 14, 2019, 12:09:57 PM »
If they were not available on Wikipedia or another source, I had to guess based on extrapolating from other locomotives or multiple units whose tractive effort is known.

Generally, it is easy to find the tractive effort of locomotives, but difficult to find the tractive effort of multiple units. I believe that I did manage to find somewhere the tractive effort for some of the "Desiro" series of multiple units (the class 450, etc.), but I could not find it for many other units, and had to extrapolate many of the other modern units from this.

How should the tractive effort look like in terms of a figure and units?

Offline Rollmaterial

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Re: IET trains does not have the correct acceleration rate and livery variants
« Reply #74 on: September 14, 2019, 01:21:14 PM »
Tractive effort is a force, so the unit is Newtons (N). You will typically find it given in kN.

Offline Freahk

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Re: IET trains does not have the correct acceleration rate and livery variants
« Reply #75 on: September 14, 2019, 07:09:32 PM »
Wiki states that it has an acceleration of  0.7m/s² and a weight of 243t (5 cars set) or 438t (9 cars set)

As 1N:=1kg*m/s², this results in a tractive effort of

243000kg*0.7m/s²=170kN (5 cars set)
438000kg*0.7m/s²=307kN (9 cars set)

Could not find acceleration data nor weight for class 801


Please let me know for which trains you need tractive effort, maybe I can assist in this.


Edit: forgot to mention about brake force.
As Wiki states class 800 has a deceleration of 1m/s² in service, or 1.2m/s² in ermergency, this would result in
243kN or 292kN (5 cars set)
438kN or 526 kN (9 cars set)

Only thing you have to do now is calculate it down to single cars as I don't know how the engines are spread over the train.
« Last Edit: September 14, 2019, 07:33:33 PM by Freahk »

Offline thegamer7893

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Re: IET trains does not have the correct acceleration rate and livery variants
« Reply #76 on: September 21, 2019, 02:48:42 PM »
Wiki states that it has an acceleration of  0.7m/s² and a weight of 243t (5 cars set) or 438t (9 cars set)

As 1N:=1kg*m/s², this results in a tractive effort of

243000kg*0.7m/s²=170kN (5 cars set)
438000kg*0.7m/s²=307kN (9 cars set)

Could not find acceleration data nor weight for class 801


Please let me know for which trains you need tractive effort, maybe I can assist in this.


Edit: forgot to mention about brake force.
As Wiki states class 800 has a deceleration of 1m/s² in service, or 1.2m/s² in ermergency, this would result in
243kN or 292kN (5 cars set)
438kN or 526 kN (9 cars set)

Only thing you have to do now is calculate it down to single cars as I don't know how the engines are spread over the train.

Nice work.

Offline jamespetts

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Re: IET trains does not have the correct acceleration rate and livery variants
« Reply #77 on: September 22, 2019, 02:54:39 PM »
Freahk - thank you for this: this is most useful.

As you may be aware, we do not have any means of simulating bi-mode traction in the game at present, so the class 800 represents this as a diesel train and the class 801 represents this as an electric train. In reality, these are almost identical save that the class 801 has fewer diesel motor cars. The Wikipedia article does not specify whether the acceleration rate given is for diesel or electric power, and I suspect the latter. I have thus adjusted the class 801's tractive effort accordingly, and used a guessed figure for the 800 (being the previous figure for the 801). I have also updated the brake force based on your calculations and corrected the weight.

If you are able to extrapolate the correct tractive effort for any other multiple unit aside from the Desiro series, that would be very helpful, as that is the only unit for which I have actual tractive effort figures, I believe (I have a vague recollection that I might have a tractive effort figure somewhere for a much older electric multiple unit, but I cannot be sure now and I cannot remember which).

Likewise, if you are able to calculate the brake force for any modern multiple units, that would be most helpful. For reference, we use the maximum service braking rate in the game, not the emergency rate.

Offline Freahk

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Re: IET trains does not have the correct acceleration rate and livery variants
« Reply #78 on: September 22, 2019, 07:18:07 PM »
Good to know.
As I don't have my computer with my C++ dev environment in range currently, I will recalculate some tractive efforts and brake forces for MUs in the next few days.

Offline Matthew

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Re: IET trains does not have the correct acceleration rate and livery variants
« Reply #79 on: September 25, 2019, 05:21:14 PM »
James, there appears to be a typo in line 11 of br-800.dat:

Code: [Select]
speed=225simutrans-pak128.britain

Offline thegamer7893

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Re: IET trains does not have the correct acceleration rate and livery variants
« Reply #80 on: September 26, 2019, 08:21:36 PM »
Freahk - thank you for this: this is most useful.

As you may be aware, we do not have any means of simulating bi-mode traction in the game at present, so the class 800 represents this as a diesel train and the class 801 represents this as an electric train. In reality, these are almost identical save that the class 801 has fewer diesel motor cars. The Wikipedia article does not specify whether the acceleration rate given is for diesel or electric power, and I suspect the latter. I have thus adjusted the class 801's tractive effort accordingly, and used a guessed figure for the 800 (being the previous figure for the 801). I have also updated the brake force based on your calculations and corrected the weight.

If you are able to extrapolate the correct tractive effort for any other multiple unit aside from the Desiro series, that would be very helpful, as that is the only unit for which I have actual tractive effort figures, I believe (I have a vague recollection that I might have a tractive effort figure somewhere for a much older electric multiple unit, but I cannot be sure now and I cannot remember which).

Likewise, if you are able to calculate the brake force for any modern multiple units, that would be most helpful. For reference, we use the maximum service braking rate in the game, not the emergency rate.

The class 801s are electric only trains.

Offline Freahk

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Re: IET trains does not have the correct acceleration rate and livery variants
« Reply #81 on: September 26, 2019, 08:46:50 PM »
Sorry but you are wrong.
Class 801 is only in service at electrified tracks but in fact, the 5 car trains and the 9 car trains, both do have one (instead of 3 or 5 in case of class 800) diesel motors installed, allowing them to continue their journey at very limited speed and providing electrical energy e.g. for light using the installed 580 kW diesel generator, which is installed under the second last car, in case tracks electrification fails.

Offline thegamer7893

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Re: IET trains does not have the correct acceleration rate and livery variants
« Reply #82 on: September 26, 2019, 10:07:38 PM »
Sorry but you are wrong.
Class 801 is only in service at electrified tracks but in fact, the 5 car trains and the 9 car trains, both do have one (instead of 3 or 5 in case of class 800) diesel motors installed, allowing them to continue their journey at very limited speed and providing electrical energy e.g. for light using the installed 580 kW diesel generator, which is installed under the second last car, in case tracks electrification fails.

Ik that but in terms of general operation the class 801 is broadly electric only

Offline Freahk

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Re: IET trains does not have the correct acceleration rate and livery variants
« Reply #83 on: September 27, 2019, 12:26:45 AM »
Where in technical terms it remains a bi-mode.

Offline thegamer7893

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[Q] IET trains does not have the correct acceleration rate and livery variants
« Reply #84 on: September 27, 2019, 10:15:51 AM »
Hello James, I have just finished playing Simutrans and I notice that the class 801 has better acceleration the the class 800 and for some reason they are not livery variant so what I mean is that the class 800 should be able to have the Virgin Trains livery and also to have the same acceleration rate as its no different in real life whether its on diesel or electric. So can that be a possible fix please?

With the acceleration corrections imminent, will it be possible to allow both the class 800/801's to be able to be liveried into either the LNER (then VTEC) livery and the GWR liveries please?

Offline Vladki

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I have got to try the class 801 (800) and found some discrepancies. (and this old thread).
Diesel engine has correct power 700 kW, but electric has 4x 226 = 904 kW, according to http://www.hitachi.com/rev/pdf/2014/r2014_10_105.pdf

Power and weight is also here (for the whole train). Power agrees with the above.
https://web.archive.org/web/20181005071852/https://www.railengineer.uk/wp-content/uploads/2017/10/Table-1-Hitachi-800-802-orders-V3-Avenir.pdf
Weights in simutrans are a little bit different, and to not sum up exactly. Was there any specific reason? Comparing the weights of 5 and 9 car trains, it seems that all powered or unpowered cars have almost the same weight (difference less than 1 t).

Also the constrainsts and upgrades are not real. There is not composite trailer but a composite motor...

Also the above document states acceleration at 0,7 deccelration 1 m/s^2.
Brake_force is set to 49, which slightly higher, than my claculation: 46.60 kN for electric, and 48.60 kN for diesel. (But I think it should be the same). So 49 kN is OK.

tractive effort: electric 77 kN, my calculation for 5-car unit is 68 kN, 9-car unit 73 kN, soooo OK... (already with gear accounted for)

But for the diesel unit it seems too low (62 kN) - with 50% gear... Given the fact thet the traction motors are the same, just the power supply is limited, we could assume that the starting acceleration could be the same (maybe only for short while). Tractive effort for 9-car diesel unit and 0.7 m/s^2 is in my calculation 61.24 kN, but without gear. So to get the same acceleration we have to multiply by 2 -> 122 kN.

Also there is a clear typo in br800-rear fixed cost (+10000 compared to others). Also I don't understand why trailers have so high fixed cost compared to motor cars? Are there any approximate rules - how much are fixed costs of staff (driver, conductor, buffet) ?

As I have finished the electrostars I will continue with these.

Offline Ranran

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Quote
Diesel engine has correct power 700 kW
Yes, it is the engine for power generation. It is driven by a motor with the generated power and the stored power.
Motor performance is as written by Valdki.

Also, as I reported in some thread before, the spec of Scott's class 385 made by inspire the next Hitachi is also different, so it would be helpful if someone fix it.
The 3-car unit and the 4-car unit are different.
The seats are different. There is no 1st class for 3-car one.
The number of motors is different. In order to have the same acceleration performance, the three-car train is a mixture of vehicles with half the number of motors. This is the method often found in Jalapagos. Feel Jalapagos.

You can check it on Hitachi's website. I think there was an English pdf somewhere. please look for it.
http://www.hitachihyoron.com/jp/archive/2010s/2016/10-11/pdf/2016_10_11_08.pdf
(This is in Japanese.)

Offline jamespetts

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Thank you for looking into this: it is very helpful to have good research on accurate data for the tractive effort of modern multiple units, and especially helpful to have implementation of this.

For the tractive effort, may I ask how you are calculating this; are you using the Simutrans physics engine and testing actual acceleration rates in-game with the parameters in question? This may be the best way to do it if we have acceleration rates but not base data and we need to infer the data from the acceleration rates.

The costs I did not set up - that was Dr. Supergood's interim balancing from a while ago; it may be that there are typing errors here.

Offline Freahk

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(starting) force is calculated using simple physical rules of mechanics:
F=m*a or in units 1N=1kg*1m/s²

Simutrans actually implements real-world physics, so apart from rounding that formula fits to simutrans as well.

Usually acceleration is given, which refers to force on tracks. Simutrans applies gear to force, thus we have to divide force by gear.

Offline Ranran

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When tested on a Japanese train example, the acceleration display in the current in-game GUI generally shows the "theoretical" acceleration value correctly.
In theory, the nominal value may differ from the theoretical value as it may actually increase or adjust the current as the vehicle loads.
Class 800 uses such an AC induction motor.
https://en.wikipedia.org/wiki/Squirrel-cage_rotor.

Offline Vladki

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For the tractive effort, may I ask how you are calculating this;
F=m*a or in units 1N=1kg*1m/s²
Exactly as Frahk says, so for example:
BR class 801, 5-car unit, 233 tons, acceleration 0.7 m/s^2 -> 233 * 0.7 = 163 kN (tractive force for the whole train). Only 3 of 5 cars are powered, so 163/3 = 54.36 kN per car. Divide by gear 54.36/0.8 = 68 kN to be written in dat file.
Decceleration 1 m/s^2 -> 233 kN / 5 cars (all braked) -> 46.6 kN per car, gear does not affect brake_force.

I used the same method for trams. This can be IMHO used for all EMUS, trams, and buses, that are not expected to pull any wagons. Calculation has to take powered/braked axles in account, not whole cars.
Also note that maximum accleration/decceleration (to avoid wheelslip) is given by weight * g (gravitation acceleration = 9.81) * steel to steel static friction coefficient. Depending on weather it cen be 0.3 (dry) to 0.1 (wet). At least czech rail design rules assume 0.15 for braking calculation purposes. For the above unit it will be 68 kN (seems like coincidence, but I don't have the numbers at hand to compare). So far all vehicles I fixed have the brake_force safely below this limit, but tractive force is sometimes higher, so the driver must be careful when accelerating in wet weather.
« Last Edit: May 25, 2020, 06:26:32 PM by Vladki »

Offline jamespetts

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That is helpful - it is good to know that the physics engine works as intended!

Offline Freahk

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it is good to know that the physics engine works as intended!
Well, apart from serious rounding troubles at low power, force or speeds at least.
The physics engine is quite impressive anyways.

Offline jamespetts

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Well, apart from serious rounding troubles at low power, force or speeds at least.
The physics engine is quite impressive anyways.

This was the work of Bernd Gabriel back in the early 2010s.

Offline Vladki

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That is helpful - it is good to know that the physics engine works as intended!
To be honest, I did not check if it works as intended. For that one would need data in form like: acceleration from 0 to 100 km/h in 10 seconds. Then one could compare if it makes it in the game.
I hope you would agree, that the values in dat files should be as close to reality as possible, and if it does not work well, then the engine has to be improved, or a global power/force factor (gear) be changed.

This is what we look for: https://eversholtrail.co.uk/fleet/class-802/
Acceleration graphs for both electric and diesel. Clearly the performance on diesel is worse...
« Last Edit: May 25, 2020, 09:12:50 PM by Vladki »

Offline Freahk

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Clearly the performance on diesel is worse...
...above roughly 30 km/h.
What's the rated speeed? Is it somewhere between 20 and 40 km/h?

If you want to validate the physics engine:
DesiroHC 4 cars RRX (class 462)
starting acceleration: 1.1 m/s²
short time power: 6000 kW
weight (empty): 200t

0-160 km/h: 72,5s


ICE3 (class 403)
starting force: 300 kN
power: 8000 kW
weight (empty): 384t
0-100 km/h: 49s
« Last Edit: May 25, 2020, 10:58:53 PM by Freahk »