kris120 wrote:There have been some discussions here about the value for </MaxForcePercentOfVehicleWeight> :
In the original, the cars have values between 70 and 80. To have more realistic values they should have about 40. Is that right ?
Kris
Here's the info I have from the AAR Brake Shoe Force Tests:
AAR requirements for freight car air brakes are outlined in S-401-99. Cars that are new, rebuilt or converted from cast iron brake shoes to composition brake shoes must have braking ratios in accordance with this document. The relevant net braking ratios for cars with high friction composition brake shoes, non-lever hand brakes, and a 30 psi brake pipe reduction from 90 psi brake pipe pressure are:
For TOFC/COFC cars: Loaded Net Braking Ratio between 11% and 13%, Max empty braking ratio 38%, minimum hand braking ratio 10%.
For all other car types: Loaded Net Braking Ratio between 8.5% and 13%, Max empty braking ratio 38%, minimum hand braking ratio 10%.
That 30 pound reduction they cite basically means brakes fully applied with a small over-reduction to make certain (since normally a 26 pound reduction would give full brakes).
For my freight rolling stock, I'm setting </MaxForcePercentOfVehicleWeight> to 13% for loaded cars and 38% for empty cars.