[Lindsayts]

I can if the forum wishes supply a method to get a reasonable performance out of the current steam code. I have applied this method to all the steamers I use and I am reasonably happy with the result.
An example is the VR loco H220, this machine weighs 146 tons, pulling a tender weighing 112 tons with a 500 ton trailing load (a passenger train). This will move off from rest at around 15% regulator, the max drawbar power seen is 3300bhp. The actual machine produced 3500 drawbar hp on a dyno car. The total steam consumption is aprox 18lbs/bhp/hour, I regard this as likely to be to high but this value is in the range expected from mainlline US locomotives (british machines almost always had lower water and fuel consumption).
The loco/s mentioned is a/are reasonably good machine/s to drive in OR.

The machines I have done so far being VR H220, SAR 500 class (South Australia), UP 4000 class (bigboy), Heisler and big shay.

Lindsay

[farrmp]

Lindsay.

Please do post your recommendations here on this Forum for all that wish to try them. I am not afraid to modify .ENG files for OpenRails use only.
I realize that down the road that the Steam Physics will improve and some of these mods may have to be 'undone'. Not a Problem!

Paul

[cjakeman]

 copperpen, on 25 August 2013 - 10:01 AM, said:

The very first thing that should be sorted for steam engines is how they actually start moving in OR. A light engine behaves like there is a very heavy train on the drawbar and takes a very large reverser and throttle setting to get moving.

That's not a bad idea. Maximum power is difficult to estimate because of the effects of speed, but the moving force at low speed and maximum cut-off is related only to the boiler pressure and the geometry of the driving gear.

We ought to be able to show what force we are delivering and compare it to the rated tractive effort. In fact, I'm adding the steam locomotive data (by steamer_ctn) to the HUD at the moment, including tractive effort.

Can you give examples of a couple of steam engines with poor starting behaviour? We will need the ENG file and the tractive effort the prototype achieved in real life.

Thanks,

[Lindsayts]

 cjakeman, on 27 August 2013 - 10:59 PM, said:

That's not a bad idea. Maximum power is difficult to estimate because of the effects of speed, but the moving force at low speed and maximum cut-off is related only to the boiler pressure and the geometry of the driving gear.

We ought to be able to show what force we are delivering and compare it to the rated tractive effort. In fact, I'm adding the steam locomotive data (by steamer_ctn) to the HUD at the moment, including tractive effort.

Can you give examples of a couple of steam engines with poor starting behaviour? We will need the ENG file and the tractive effort the prototype achieved in real life.

Thanks,

The problem (I THINK) is the Data in the Forcefactor2 Interplolator is incorrect and is to high, this is putting excesive back pressure in the cylinders making the machines hard to start and perform quite poor. AS stated one CAN get around this, as has been stated already a lot of steamers are VERY poorly setup something that OR cannnot tolerate as OR is expecting accurate data in the set up.

I will put up a set up system I use to provide steamers that work correctly. I have been sidetracked momentarily by trying to use the Boilereffiecency interpolator. Unfortunately defining this has triggered a bug in the AI firing, and I am just trying to work out what to do next as sadly I have not and do not look like being able to get a C# complier.

The method I use sets up a steamer almost an exact replica in peformance of a US mainline loco from the late 1920s to the 2nd world war including correct water consumption and almost correct power ,its down around 10 percent actually no big issue really one can actual get 7000 bhp out of a UP Bigboy with a tolerably reasonable water consumption. This being its correct power output.

I was trying to get the boilereffiecency to work as if this can be done this will effectively produce an excellent steam physics model in the existing code base.

Lindsay

[copperpen]

 cjakeman, on 27 August 2013 - 10:59 PM, said:

That's not a bad idea. Maximum power is difficult to estimate because of the effects of speed, but the moving force at low speed and maximum cut-off is related only to the boiler pressure and the geometry of the driving gear.

We ought to be able to show what force we are delivering and compare it to the rated tractive effort. In fact, I'm adding the steam locomotive data (by steamer_ctn) to the HUD at the moment, including tractive effort.

Can you give examples of a couple of steam engines with poor starting behaviour? We will need the ENG file and the tractive effort the prototype achieved in real life.

Thanks,

The default Scotsman should do as an example. Just about every MSTS steam eng file is derived from it.

[Lindsayts]

I will post my "recommendations" (for what they are worth) in the "OR physics" forum.

Lindsay

[cjakeman]

 copperpen, on 28 August 2013 - 02:32 AM, said:

The default Scotsman should do as an example. Just about every MSTS steam eng file is derived from it.

I see Wikipedia gives the Tractive Effort as 29,385 lbf.

Does anyone know where I can find measured performance data for this famous loco?

Thanks,

[copperpen]

The Wiki article has a mix of A1 class (original) and A3 class (rebuild) data. As an A3 the weight increased to 96t-5cwt, BP went up to 220psi and the TE increased to 32,909 lbf.
The Flying Scotsman as modelled is an A1 so the data should be weight - 92t-9cwt, BP 180psi and TE 29835 lbf.

As for actual performance data that is not so easy to come by. If I locate any I will post here.

[cjakeman]

 copperpen, on 29 August 2013 - 03:36 AM, said:

The Wiki article has a mix of A1 class (original) and A3 class (rebuild) data. As an A3 the weight increased to 96t-5cwt, BP went up to 220psi and the TE increased to 32,909 lbf.
The Flying Scotsman as modelled is an A1 so the data should be weight - 92t-9cwt, BP 180psi and TE 29835 lbf.

Thanks, Copperpen.

I found some info more detailed than Wikipedia and that shows the A1 with a 20" cylinder diameter and the TE you quoted. I note that MSTS scotsman.eng has the cylinder diameter as 19" which affects the TE.

If we restore the cylinder to 20", we can run the loco to see its TE (please use the latest v1726) and see how much it falls short of 29,835.

[Lindsayts]

 cjakeman, on 29 August 2013 - 11:59 AM, said:

Thanks, Copperpen.

I found some info more detailed than Wikipedia and that shows the A1 with a 20" cylinder diameter and the TE you quoted. I note that MSTS scotsman.eng has the cylinder diameter as 19" which affects the TE.

If we restore the cylinder to 20", we can run the loco to see its TE (please use the latest v1726) and see how much it falls short of 29,835.

A couple of points to keep in mind here....

Almost all tractive effort figures published are calculated, and differing works DID use different formulas. Second in no published performance figures is there any sign of how the TE behaves at speed, in this respect from what data I do have is that British and a lot European loco's were signifcantly ahead of there US counterparts in both drawbar power and water conumption.

A real good thing to look out for is run figures that publish the train weight and speed partcularly on up grades as these can be used to get a good an idea of how the machine __REALLY__ peforms. High detailed test data for steam locos is __VERY__ rare and basicly non-existent for saturated steam loco's. The only nearly complete data I have is for Pensylvania RailRoad K4s from the late 1920's, There is around half a dozen spot power figures for another half a dozen or so machines.
The book Articulated locos by Weiner does contain quite a few load and speed figures on grades for both superheated and saturated machines.

I found water consumption figures for American machines are virtually no existent, although "Steam Locomtives" by Johnson does have a few, unfortuaately most without a clear ID of the loco concerend.

A lot of steam loco data does not even publish the grate area, probably the most important stat of the whole machine.

All this makes an accurate simulation of a steamer quite difficult to achieve.

Lindsay