[jorgen]

I have noticed that when starting the long trains so is the friction on the wagons very high and when you get up to about 5 mph, it becomes normal.
I had 130 cars and drove on an uphill slope with no problems for 15 mph
but when I stopped and would acceleration again so could not locomotives move the train.

One sees in F5 HUD that friction is large up to 5 mph. Then it increases again with increasing speed.
My guess is that friction is maybe a little bigger right at the moment of starting on a train.
But it is 10 times as high as at 5 mph I do not know if I agree.
The value of the friction in the carriages F5 HUD is about 6000 at 0 mph and about 500 at 5 mph.

This post has been edited by jorgen: 04 March 2014 - 11:51 AM

[copperpen]

What you are seeing is correct behaviour for the friction curve. High at rest, dropping to a low point at about 5mph at which point mechanical friction is low, then slowly increasing with air resistance as speed increases. Friction is something that now has to be taken into account when making up a train.

[Matej Pacha]

Well, there are two main reasons for this - first is the WAG file friction setting, which can be too high, the second could be the curve friction setting in the ORTS Options menu/Simulation. If you need assistance, the ORTS log file would be very heplful, as well as the WAG file (or just some part of it) used in your activity/run.

Anyway, this behavior is closer to the real world.

Cheers,

Matej

[mozdonyos]

I'd noticed that after starting ignores the Friction hand, but the "Mass" of count for something.
Pre-X1935-Series edition friction model was more realistic in this regard.
The current version is much smaller than the real trains can carry only.

Do not be angry with me because of the language I use a translator

[jorgen]

Matej Pacha, on 04 March 2014 - 10:05 PM, said:

Well, there are two main reasons for this - first is the WAG file friction setting, which can be too high, the second could be the curve friction setting in the ORTS Options menu/Simulation. If you need assistance, the ORTS log file would be very heplful, as well as the WAG file (or just some part of it) used in your activity/run.

Anyway, this behavior is closer to the real world.

Cheers,

Matej

Hi
Here are two of the wagons in the train and log file.
2 engine (SD90) and 124 wagons 8000 ton. I need 60-80% power to move train from stop . No gradient
Thanks for all help.
This simulator is very good and you are doing an incredible job in order to improve the simulator all the time
Looking forward to drive Open Rails 1,0

Wagon 1
Wagon ( TTX_HuskyStack_1a
Type ( Freight )

comment( 24.09t empty, 47.9t full )
Mass ( 47.9t )

)
Velocity ( 0.1m/s )
)
Adheasion ( 0.2 0.4 2 0 )
DerailRailHeight ( 4cm )
DerailRailForce ( 2.5*48t )
DerailBufferForce ( 300kN )
NumWheels ( 4 )
Friction (
495N/m/s 0 1mph 9.96N/m/s 1.8
5.1N/rad/s 1 -1rad/s 0 1

wagon 2
Wagon ( 3dts_spwellcar_china
comment( Flat Car )
Type ( Freight )

comment( 12.97t empty, 50.97t full )
Mass ( 81.97t )

)
Velocity ( 0.1m/s )

)
Adheasion ( 0.2 0.4 2 0 )
DerailRailHeight ( 4cm )
DerailRailForce ( 2.6N/kg*80t )
DerailBufferForce ( 430kN )
NumWheels ( 8 )
Friction (
597N/m/s -0.1 1.5mph 5.14N/m/s 1.938
5.1N/rad/s 1 -1rad/s 0 1

Attached File(s)

•  OpenRailsLog.txt (12.25K)
  Number of downloads: 244
•  dump.txt (1.35MB)
  Number of downloads: 245

This post has been edited by jorgen: 05 March 2014 - 09:13 AM

[Genma Saotome]

jorgen, on 05 March 2014 - 08:30 AM, said:

Mass ( 47.9t )
Friction (
495N/m/s 0 1mph 9.96N/m/s 1.8
5.1N/rad/s 1 -1rad/s 0 1

I took a look at the above... the friction data there is wildly low... almost 200% below what it should be at starting speeds, "only" 75% below what it should be at 5mph and degrading to 200% below what it should be by 58 mph.

That's why it was so easy to pull before.

for 47.9t the data for the first line of friction() should be something like this:
1075N/m/s -0.265 5.650mph 6.190N/m/s 1.653

These values give starting resistance at 1.75% below what should be expected, 3% above at 7mph, and +- 0.1% from 18-60mph.

The first three elements position the resistance curve from starting to around 15mph, the last two deal with 15-60+ mph. Just glancing at the difference should point out how different the original values are relative to something more realistic.

[Lindsayts]

Just a curious question, how much force does this equate to in real life. Some time back we had to do some work in a rail yard and had to shift a unloaded bogie flat wagon fitted with roller bearings. Two of us managed to get it moving. but one does have to push for a while to do so. We moved it this way successfully and ended up stopping it with the handbrake. From memory the wagon weighed around 10 tons the force we applied would have been less han 80Kg. I remember being amazed at the time that so little force was required to get it started. Its a REAL GOOD demonstration of inertia though.

I have not tried this with plain bearing wagons I would not be surprised if it was far more difficult proposition.

Lindsay

[jtr1962]

Lindsayts, on 05 March 2014 - 01:07 PM, said:

Just a curious question, how much force does this equate to in real life. Some time back we had to do some work in a rail yard and had to shift a unloaded bogie flat wagon fitted with roller bearings. Two of us managed to get it moving. but one does have to push for a while to do so. We moved it this way successfully and ended up stopping it with the handbrake. From memory the wagon weighed around 10 tons the force we applied would have been less han 80Kg. I remember being amazed at the time that so little force was required to get it started. Its a REAL GOOD demonstration of inertia though.

I have not tried this with plain bearing wagons I would not be surprised if it was far more difficult proposition.

Lindsay

As a very general rule, for roller-bearing wagons at low speeds the friction force is very roughly 20 pounds per axle plus a pound for every ton of mass. For this wagon then the friction should be in the area of 90-100 pounds, or 40-45 kg. Starting friction would probably be somewhat higher but less than 80 kg sounds about right. It's actually a great demo of how efficient railways are at moving goods and people to show 2 men starting and pushing a wagon which weighs as much as a truck. In fact, it's not outside of the realm of possibility for two men to start a 100-ton locomotive.

[jorgen]

Solid Bearings and roller Bearings on wagons have difference in friction on low speed i think?
i have read Methodology and Theory of FCalc 2.0

According Fcalc 2:0 so is a wagon with solid bearings 50 tons 0 mph
1094.0N/m/s -0.25 5.5mph 19.678N/m/s 1.000
The same carriage with roller bearing
690.3N/m/s -0.10 1.5mph 10.966N/m/s 1.000

That makes you curious how much of the wagons of the United States who have
Solid bearings.

2 people can pull a locomotive of 100 tonnes
160-200 people would be able to pull a train 8,000 tons no slope.
if all cars have roller bearings. Have I right here!

But if the cars had solid bearings, they have not any changes to pull the train at all I think.
In my case, I needed to 7000-8000 hp (60-80% power 2 locomotives) to move the train.
i slowly increased the power on locomotives

[Lindsayts]

jtr1962, on 05 March 2014 - 01:29 PM, said:

As a very general rule, for roller-bearing wagons at low speeds the friction force is very roughly 20 pounds per axle plus a pound for every ton of mass. For this wagon then the friction should be in the area of 90-100 pounds, or 40-45 kg. Starting friction would probably be somewhat higher but less than 80 kg sounds about right. It's actually a great demo of how efficient railways are at moving goods and people to show 2 men starting and pushing a wagon which weighs as much as a truck. In fact, it's not outside of the realm of possibility for two men to start a 100-ton locomotive.

The makers of the Tornado the newly built A1 locomotive (in Britain) have stated just that, ie the loco can be pushed by hand. The web site also states if the loco is suspended the driving wheels can be turned by one person. Note, one of the changes they made was to use roller bearings where ever possible.

Plain bearings if well maintained and have good lubrication are from my experience not far behind. Before the days of large semcinducor invertors we had what was called a No break set installed, this provided 30 KW of AC power continously regardless of the state of the mains. THe Machine consisted of a 50bhp AC motor, a 50bhp 130Volt DC motor and a 30 KVA altenator. The bearings on all machines were bronze bushes lubricated from a resivior of oil (Shell turbo 33 was used) by a steel ring running on the shaft. During the rare periods when the machine was stopped for maintence one could turn the machine by hand without difficulty from one of the coupling flanges between the machines, inspite of the fact the rotating mass must have been around 2 or 3 tons and the driving flanges only being around 20cm diameter.

Lindsay