Some changes include:
i) Change HUD to display vacuum piped vehicles correctly (currently appear as air piped wagons)
ii) Introduction of new controller - to simulate controller fitted to BR steam locomotives
iii) Revision of code to now correctly respond to pipe charging values - currently uses air brake code, and logic appeared to be reversed for vacuum operation
iv) Allowance for vacuum brakes to operate without an equalising reservoir, as most vacuum brake systems did not have equalising reservoir
v) Calculation of brake system volumes, and adjusting timing parameters depending upon variation of brake system volume, and thus braking performance
More detailed information on the changes, and the relevant parameters will follow at some stage in the future.
In the meantime the following executive summary is provided.
ENG Parameters -
In addition to "normal engine" parameters, the following have been added:
ORTSBrakePipeChargingRate - Sets rate at which brakepipe charges (ie. Brake releases ), this should be calculated based upon a trains with a brake system volume of 200ft^3, so that timing parameter variation can be correctly calculated
ORTSBrakeServiceTimeFactor - Sets rate at which brakepipe discharges under normal operation (ie. Brake applies )
ORTSBrakeEmergencyTimeFactor - Sets rate at which brakepipe discharges under emergency operation (ie. Brake applies )
ORTSBrakePipeTimeFactor - Impacts rate of vacuum propagation time along train
BrakesTrainBrakeType - Determines whether equalising reservoir is used or not, setting requires - "vacuum_single_pipe_eq". Off by default.
Note: Brake will not experience leakage if no value is assigned for TrainPipeLeakRate in the ENG file.
WAG Parameters -
In addition to "normal wagon" parameters, the following have been added:
ORTSDirectAdmissionValve - Car has direct admission valves fitted - set 0=false, 1=true
ORTSNumberBrakeCylinders - Number of brake cylinders fitted to wagon - set as integer value
ORTSBrakeCylinderSize - Size of brake cylinders fitted to wagon
ORTSAuxilaryResCapacity - Volume of vacuum reservoir
All of the above have standard default values, so they only need to be varied if performance variations are required.
To achieve the most realistic braking performance, it is important that the correct controller configurations are used. The relevant controller parameters, as found on common prototype control valves, have been defined in the code, and need to be selected by the user as appropriate.
The following two are suggested as a possible starting point.
BR Standard Vacuum brake Controller - 2 position - ON and OFF, variable between these two points
Brake_Train ( 0 1 0.1 0.4 NumNotches( 1 Notch(0 1 TrainBrakesControllerVacuumContinuousServiceStart ))) )
Dreadnought Ejector - 3 position - RELEASE, RUNNING (A lap position where vacuum remains at the same value, depending upon the TrainPipeLeakage), APPLICATION
Brake_Train ( 0 1 0.3 0.4 NumNotches( 3 Notch(0 0 TrainBrakesControllerReleaseStart ) Notch(0.3 0 TrainBrakesControllerRunningStart ) Notch(0.6 0 TrainBrakesControllerApplyStart )))
Normally these were operated on non-EQ brake systems.