Open Rails - Standard Resistance Force Parameters
Aim - this section describes the basic standard physics parameters required to correctly define resistance forces in Open Rails Train Simulator.
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Index
Curve Resistance and Speed Limit
Trailing Locomotive Resistance
Note: The default unit of measure (UoM) shown in the "Recommended Input Units" column is the UoM value that OR assumes if no UoM is included in the parameter statement.
Parameter | ENG or WAG | Description | Recommended Input Units | Suggested settings | New or Existing | Typical Examples |
---|---|---|---|---|---|---|
Standard Resistance | ||||||
ORTSBearingType ( x ) | WAG | Describes the type of bearing fitted to the wheelsets on the wagon. | Text | As per wagon specification. x = Roller - standard roller bearing, x = Low - low friction bearing, x = Friction - friction or journal (plain) oil bearing, x = Grease - friction or journal (plain) grease bearing. | New | ORTSBearingType ( Friction ) |
ORTSDavis_A ( x ) | WAG | Davis Constant A. | Force - N, kN, lbf, lb Default - N | As per wagon specifications. (FCalc is used to calculate standard resistance values.) | New | ORTSDavis_A ( 502.8N ) ORTSDavis_A ( 502.8lb ) |
ORTSDavis_B ( x ) | WAG | Davis Constant B. | Resistance - N/m/s, lbf/mph Default - N/m/s | As per wagon specifications. (FCalc is used to calculate standard resistance values.) | New | ORTSDavis_B ( 1.5465N/m/s ) ORTSDavis_B ( 1.5465lbf/mph ) |
ORTSDavis_C ( x ) | WAG | Davis Constant C. | ResistanceDavisC - Nm/s^2, lbf/mph^2 Default - Nm/s^2 | As per wagon specifications. (FCalc is used to calculate standard resistance values.) | New | ORTSDavis_C ( 1.43Nm/s^2 ) ORTSDavis_C ( 1.43lbf/mph^2 ) |
ORTSNumberDriveAxles ( x ) | ENG | Number of driven axles on the locomotive. (Any non-driven axles will use the following parameter) | Number | As per locomotive Specs | New | ORTSNumberDriveAxles ( 4 ) |
ORTSNumberAxles ( x ) | WAG | Number of axles on the wagon. (Or non-driven axles on a locomotive) | Number | As per wagon Specs | New | ORTSNumberAxles ( 4 ) |
WheelRadius ( x ) | WAG | Radius of wheels. | Distance - m, cm, mm, km, in, ft, in/2 Default - m | As per wagon Specs | Existing | ORTSNumberAxles ( 4 ) |
ORTSDriveWheelWeight ( x ) | ENG | Total weight on the locomotive driving wheels | Mass - lbs, kg, t, t-uk, t-us Default - kg | As per loco specs | New | ORTSDriveWheelWeight ( 2.12t ) ORTSDriveWheelWeight ( 4000.0lb ) ORTSDriveWheelWeight ( 2000.0kg ) NB: can be left out if not known |
Curve Resistance and Speed Limit | ||||||
CentreOfGravity ( x y z ) | WAG | Describes the centre of gravity for the vehicle. | Distance - m, cm, mm, km, in, ft, in/2 Default - m | As per wagon specifications. (Measuring CoG) Distance from central reference point, x = distance "across train", y = height above track, z = distance "along train". | Existing | CentreOfGravity ( 0.0m 2.0m 0.0m ) |
ORTSTrackGauge ( x y ) | WAG | Track gauge. | Distance - m, cm, mm, km, in, ft, in/2 Default - m Note - must have both parameters x & y | As per track specifications. | New | ORTSTrackGauge ( 4ft 8.5in ) ORTSTrackGauge ( 1.0m 435.0mm ) |
ORTSRigidWheelbase ( x y ) | WAG | Fixed wheelbase of bogie or steam locomotive. | Distance - m, cm, mm, km, in, ft, in/2 Default - m Note - must have both parameters x & y | As per track specifications. | New | ORTSRigidWheelbase ( 0.0ft 56in ) ORTSRigidWheelbase ( 0.0m 900.0mm ) |
ORTSUnbalancedSuperelevation ( x ) | WAG | Cant deficiency specifies the additional speed that a train can travel around a curve without exceeding passenger comfort. Tilt trains for example have higher cant deficiences. | Distance - m, cm, mm, km, in, ft, in/2 Default - m | As per wagon specifications. Typically between 0 & 12 inches. | New | ORTSUnbalancedSuperelevation ( 6in ) |
ORTSTrackSuperElevation ( x1 y1 .. xn yn) | TRK | Track superelevation for different radii curves. | x = curve radius (in metres), y = superelevation (in mm). As many x,y pairs may be included in this parameter as desired. | As per track design specifications. | New | ORTSTrackSuperElevation ( 0.0 0.00 50.0 0.0 300.0 0.025 400.0 0.025 500.0 0.050 1000.0 0.075 2000.0 0.100 10000.0 0.100 ) |
Tunnel Resistance | ||||||
ORTSSingleTunnelArea ( x ) | TRK | Cross section area of single track tunnel. | AreaDefaultFT2 - ft^2, m^2 Default - ft^2 | As per track standards. | New | ORTSSingleTunnelArea ( 27.0m^2 ) ORTSSingleTunnelArea ( 2225.0ft^2 ) |
ORTSDoubleTunnelArea ( x ) | TRK | Cross section area of double track tunnel. | AreaDefaultFT2 - ft^2, m^2 Default - ft^2 | As per track standards. | New | ORTSDoubleTunnelArea ( 45.0m^2 ) ORTSDoubleTunnelArea ( 2225.0ft^2 ) |
ORTSSingleTunnelPerimeter ( x ) | TRK | Perimeter of single track tunnel. | Distance - m, cm, mm, km, in, ft, in/2 Default - m | As per track standards. | New | ORTSSingleTunnelPerimeter ( 21.3m ) ORTSSingleTunnelPerimeter ( 65.0ft ) |
ORTSDoubleTunnelPerimeter ( x ) | TRK | Perimeter of double track tunnel. | Distance - m, cm, mm, km, in, ft, in/2 Default - m | As per track standards. | New | ORTSDoubleTunnelPerimeter ( 21.3m ) ORTSDoubleTunnelPerimeter ( 65.0ft ) |
Wind Resistance | ||||||
ORTSWagonFrontalArea ( x ) | WAG | Cross section area car. | AreaDefaultFT2 - ft^2, m^2 Default - ft^2 | As per car plans. | New | ORTSWagonFrontalArea ( 10.0m^2 ) ORTSWagonFrontalArea ( 120.0ft^2 ) |
ORTSDavisDragConstant ( x ) | WAG | Drag constant for wind resistance. | Constant | As per railway standards. | New | ORTSDavisDragConstant ( 0.0024 ) |
Trailing Locomotive Resistance | ||||||
ORTSTrailLocomotiveResistanceFactor ( x ) | WAG | Constant for trailing locomotives. | Constant | As per railway standards. | New | ORTSTrailLocomotiveResistanceFactor ( 0.20833 ) |