CSX Ethanol train physics

[R. Steele]

I have been very interested in this thread as physics are a priority for me.

Why not use pounds for mass instead of tons?

My understanding is that OR accepts many UoM, see pages 219-221 Sec22.1 Units of Measure.
Reading that section you'll find that OR does indeed accept lbs for certain parameters.
You can choose to use any that is appropriate for a specific parameter, however, the only UoM that does not have to be explicitly expressed is the default UoM - all others have to be specified.
My choice was to use the default at all times, and stick to metric UoM

[greg_davies]

To wrap up, I did some research to find some real values for Coupling Break(). Based on the ORTS Manual, the Unit of Measure can be N for or kN for Newtons and lb or lbf for Pounds. There are conversion apps on the web to go between either.

Couplers are made to AAR M-211 Standards
Grade C knuckle, 300,000 lbs, and coupler 450,000 lbs.;
Grade D knuckle, 350,000 lbs, and coupler 600,000 lbs.;
Grade E knuckle, 400,000 lbs, and coupler 700,000 lbs.;
Grade F knuckle, 650,000 lbs, and coupler 900,000 lbs.;
Grade H knuckle, 650,000 lbs, and coupler 900,000 lbs.

Modern cars are generally equipped with F Type or Grade F couplers, that includes engines, coal and tank cars plus others.
Grade or Type H couplers are found on Passenger equipment and are considered "Tight Coupling" to keep cars coupled during derailments. I could not find anything on these so I used the Type F settings.
A lot of equipment running today are equipped with E Type couplers. There is an E/F Type which is basically a Type E for our calculations.
The Type C and D couplers are "Steam Era" type couplers.

These values are not validated with anything "official". The values are derived from various "un-official" sources. The values that we would use would be the Knuckle break values. The general idea is to break the knuckle before the coupler itself or any other part. Knuckles can be replaced easier in much less time and cost.

If you have better information, please share it. This is the best I could come up with in a short period of time. I think it is a good point to start and the values seem to be realistic. For what it is worth......

Greg Davies

[geepster775]

H is a tightlock version of F, used primarily on passenger trains (Acela, Amfleet, etc)

F is a freight version of H with a top shelf design, which I believe is used on some rotary coupler cars, newer standard crude tank cars or other specialty application where you have tri-axle freight car trucks or greater. Situations like Schnabel cars where the loads are massive and weight is carried across 48 axles, or even a heavy duty 8 axle flatcar.

E is the common one for coal service or general 286K cars. I've seen figures as high as 450,000 for these. So I'm okay with Jason's 420,000 selection for those.

D is still in use today on lesser grade freight cars. This is the value Jason should be using for the lesser cars like gondolas and high cubes. His 250,000 value is low.

C is from the 40 foot, 70 ton boxcar era of the 1950s-1970s. They were still quite common into the 80s and 90s.

I managed to get a shot of a relatively new CNW AC4400 that had wandered away from home, and the relatively clean rear end plate had multiple holders for spare E knuckles only. These are on coal service units.