Help making ORTS eng file

[DuctTapeGuru]

I just bought the BLW/ZT CF7 set, and was wondering if I could get some help making an ORTS eng file for it. I'm using the ORTS file from Tyler Bundy's GP10 series, modified as well as I can for a CF7.

FWIW, I have been following the ORTS engine file threads, but I'm still not particularly confident when it comes to doing this myself.

Thanks in advance.

[R. Steele]

Any specific questions you have? I may be able to help, can't guarantee it.

[Erick_Cantu]

I have a 16-567B/BC engine block that you can use, if that helps, it's posted here.
I don't know that any of the other GP7 parameters might necessarily apply to the CF7.

[DuctTapeGuru]

Thanks for the files Eric. They're a big help.

Gerry, this is the area I don't understand at all and need some help with (from Tyler Bundy's GP10 .eng file):

ORTSAdhesion ( ORTSSlipWarningThreshold ( 70 ) )
ORTSAdhesion ( ORTSCurtius_Kniffler ( 7.5 44 0.161 0.7 ) )
ORTSBearingType ( Roller )
ORTSDavis_A ( 1233.06 )
ORTSDavis_B ( 37.0181 )
ORTSDavis_C ( 8.386521 )

Have no idea how one calculates the Davis parameters.

[dcarleton]

Have no idea how one calculates the Davis parameters.

If you have fcalc, the third tab from the left is 'View', and the first option is 'Davis Coefficients'. Hard to believe it's been hiding there the whole time!

[R. Steele]

Yes, as David said ( post #5) use FCalc2 (here in library fcalc.zip ) to calculate the Davis values. Make sure your "front area" is as accurate as you can make it. In the "view" dropdown menu, besides the Davis option, are all the graphs and information used to produce the program -- good reading for a deeper understanding. Also make sure to read the methodology and readmes found in the "help" dropdown.

Keep the UoM metric for FCalc ( file dropdown menu selection) - that way the values can be copied over without having to add a UoM suffix to every parameter.

I always use 105km/h for speed, because it is at this point that air drag becomes important. If the curve is set for this speed, it is most accurate at all speeds. ( I hope that's technically correct)

One last item - I'm a pest about this point - please use the Comment ( Assumptions ... ) line after the ORTSDavis numbers.

Comment ( == Assumptions -Locomotive diesel/electric - speed - 65mph (105km/h), Roller Bearing, 6 axles, frontal area - 14.1m2, WagonWeight - 170.6 ton (metric), Drag 1.0 == )

This provides others with insight to your data, how you arrived at the parameters, and a means to verify what they are using. Also keeps the data sources open and available to all. I first found this on Peter Newells web site...an excellent idea.

The Curtius Kniffler numbers are empirical numbers. I've seen threads, read the studies on how they were derived ( numerous real-world tests over a period of years by the rail industry) -- Leave the values as ( 7.5 44 0.161 0.7 ), they are correct for almost all situations - they get you in the ballpark. There is minimal need to change them for wagons...any contemplated changes would be for engine files.
When you feel you've made sufficient progress with understanding the ORTS Engine, then start thinking about making small adjustments, tinker with them.
This refers to engine files only >>> The best reference source I've been provided with, only changes the first two values ( A & B) and keeps C & D "locked". I'm still trying to understand that, myself.

Good explanation on adhesion here >>> http://www.coalstonewcastle.com.au/p...team-adhesion/

Check out the Curtius Kniffler (adhesion) threads at ET
here's one >>> http://www.elvastower.com/forums/ind...urtius__st__10

OR accepts three kinds of bearings, Roller, Friction, and Low ( for low torque)...I know BLW_ZT equipment prefer Friction, most everything else is Roller, although I've seen Low used...but have no documentation on why it was used. Perhaps someone reading this can provide an explanation about the uses of Low Torque bearings...what era of equipment, and why/when they were used.

ORTS slip warning threshold default is 70 .... I am still using this. Just have not gotten around to testing different values.
I good route to test all this on is Peter Newells (steamer_ctn) excellent test route.

http://www.coalstonewcastle.com.au/physics/route/

The route is bare-bones, precisely/carefully constructed to provide long consistent grade, loads easily. You can populate is with your own test stock and equipment you wish to test.
Peter's site is also the must read place to start understanding the basics of OR physics.

http://www.coalstonewcastle.com.au/

Besides gaining an understanding of the usefulness of the ORTS specific parameters, you should start to learn the usefulness of the include file, the OpenRails folder, and the common OR folder. Together these three create an extremely flexible "modular" system that allows you to tailor your trainset (or trainsets) to OR native physics, without having to disassemble all the all original MSTS eng and wag files.
Also it allows changes to be made quickly and easily across a whole fleet of equipment.