Vacuum BrakeControllers
Aim - this section describes some common brake control positions, and how they can be modelled within the Open Rails
The BrakeControllers are used to model the control valve positions on typical train or locomotive (engine) brake controllers.
Index
Standard British Rail Brake Controller (Gresham & Craven - SSJ Controller)
Standard London North Eastern Railway (LNER) Brake Controller
Eames Non-Automatic (Straight) Vacuum Brake Controller
Hardy Non-Automatic (Straight) Vacuum Brake Controller - Single Ejector
Hardy Non-Automatic (Straight) Vacuum Brake Controller - Twin Ejector
Introduction
Over the years various brake systems have been developed. To control these brake systems various brake control valves were used to allow the locomotive driver to control the operation of the brakes. Older brakes tended to use air valves, whereas more modern systems have electrical (electronic) switches. The control valves or switches had multiple positions which allowed the driver to release or apply the brake under different scenarios.
Open Rails attempts to emulate the operation of these valves or switches by providing a number of brake control tokens which can be defined in the
This page shows the brake control token that are thought to be used currently by Open Rails to define each of the relevant brake controller types. This is currently a work in progress, so any relevant feedback is welcomed through the contact page.
The brake system with an EQ reservoir has three timing components as follows, each of which will need some form of adjustment in OR:
- Equalising Reservoir - sets the desired vacuum to be applied to the BP (uses independent timing value for increasing and decreasing the vacuum level)
- BP charging rate - time for the brake pipe to be charged
- BP propagation rate - time for the vacuum to propagate from the front to the rear of the train
Standard British Rail Brake Control (Gresham & Craven SSJ Controller)
This type of brake system controller was typically fitted to British Rail steam locomotives, and used a Gresham & Craven SSJ Ejector with a standard BR control valve.
The control valve had two positions, "ON" and "OFF", and was "graduable", thus it could be moved to any position and the vacuum would be maintained at the level which corresponded to this position between the ON and OFF positions.
Automatic Brake Valve Controller () (Train Brake)
| Brake Valve Position | State | OR BrakeContoller Type |
|---|---|---|
| Brake OFF | The BP vacuum is "held at" 21 in Hg or increased to that value when the driver has the brake in this position due to the action of the ejectors. | |
| Graduable between ON and OFF | The brake valve is put in a position between the ON and OFF positions. | TrainBrakesControllerVacuumContinuousServiceStart |
| Brake ON | The BP vacuum is destroyed and the brakes are applied to stop the train. |
Timing Parameters
The above train brake uses the following timing parameters in the
Release - rate of release is the net sum of the following values = Large Ejector + Small Ejector - Brake Pipe Loss. The rate of vacuum creation will be dependent upon the settings in the
Application - rate of application is based upon the ratio of
Independent Brake Valve Controller () (Engine Brake)
Typically a steam brake was applied to the locomotive and tender, which functioned as an Independent brake. This brake could be operated independently of the train brake. If a separate locomotive brake is not fitted, then the EngineBrakeController parameters can be removed from the
| Brake Valve Position | State | OR BrakeContoller Type |
|---|---|---|
| Brake OFF | The "Brake Off (Release)" position releases the brake. | |
| Graduable between ON and OFF | The steam pressure is maintained at the rate depending upon the valve position. | EngineBrakesControllerBrakeNotchStart |
| Brake ON | The "Brake On (Apply)" position applies the brake, independently of the train brake. |
Timing Parameters
The above locomotive brake uses the following timing parameters in the
For an example of this type of brake configuration and operation see the DoG locomotive on the stock page.
Standard Great Western Railway (GWR) Brake Controller (Gresham & Craven - Dreadnought Ejector Controller)
This type of brake system controller was typically fitted to Great Western Rail steam locomotives, and used a Gresham & Craven Dreadnought Ejector with a Dreadnought control valve.
The control valve had three positions, "ON", "RUNNING" and "OFF". thus it could be moved to any position and the vacuum would be maintained at the level which corresponded to this position between the ON and OFF positions.
Automatic Brake Valve Controller () (Train Brake)
| Brake Valve Position | State | OR BrakeContoller Type |
|---|---|---|
| Brake OFF | The BP vacuum is "held at" 25inHg or increased to that value when the driver has the brake in this position due to the action of the ejectors and vacuum pump. | TrainBrakesControllerReleaseStart |
| Brakes ON | The BP vacuum is destroyed at a variable rate depending upon how far that the controller valve is moved towards the ON position. | TrainBrakesControllerVacuumApplyContinuousServiceStart |
Timing Parameters
The above train brake uses the following timing parameters in the
Release - rate of release is the net sum of the following values = Large Ejector + Small Ejector - Brake Pipe Loss. The rate of vacuum creation will be dependent upon the settings in the
Application - rate of application is based upon the ratio of
Independent Brake Valve Controller () (Engine Brake)
No independent locomotive brake was fitted, so for this configuration parameters related to the locomotive brake can be left out of the
For an example of this type of brake configuration and operation see the Hall locomotive on the stock page.
Standard London North Eastern Railway (LNER) Brake Controller
This type of brake system controller was typically fitted to Great Western Rail steam locomotives, and used a Gresham & Craven Dreadnought Ejector with a Dreadnought control valve.
The control valve had three positions, "ON", "RUNNING" and "OFF". thus it could be moved to any position and the vacuum would be maintained at the level which corresponded to this position between the ON and OFF positions.
Automatic Brake Valve Controller () (Train Brake)
| Brake Valve Position | State | OR BrakeContoller Type |
|---|---|---|
| Brake OFF | The BP vacuum is "held at" 25inHg or increased to that value when the driver has the brake in this position due to the action of the ejectors and vacuum pump. | TrainBrakesControllerReleaseStart |
| RUNNING | The BP vacuum is held at the level that the BP has reached when the control valve is moved to the RUNNING position. | TrainBrakesControllerRunningStart |
| Brakes ON | The BP vacuum is destroyed at a variable rate depending upon how far that the controller valve is moved towards the ON position. | TrainBrakesControllerVacuumApplyContinuousServiceStart |
Timing Parameters
The above train brake uses the following timing parameters in the
Release - rate of release is the net sum of the following values = Large Ejector + Small Ejector - Brake Pipe Loss. The rate of vacuum creation will be dependent upon the settings in the
Application - rate of application is based upon the ratio of
Independent Brake Valve Controller () (Engine Brake)
An independent locomotive brake was fitted to steam braked locomotives, but omitted for vacuum braked units.
| Brake Valve Position | State | OR BrakeContoller Type |
|---|---|---|
| Brake OFF | The "Brake Off (Release)" position releases the brake. | |
| Graduable between ON and OFF | The steam pressure is maintained at the rate depending upon the valve position. | EngineBrakesControllerVacuumContinuousServiceStart |
| Brake ON | The "Brake On (Apply)" position applies the brake, independently of the train brake. |
For an example of this type of brake configuration and operation see the V2 locomotive on the stock page.
Eames Non-Automatic (Straight) Vacuum Brake Controller
This type of brake system controller was typically fitted to older steam locomotives, and used two control valves. The first valve was to control releasing of the brakes, and the second valve was to control application of the brakes using a steam ejector.
Both control valves had two positions, "ON" and "OFF".
Brake Valve Controller () (Train Brake)
| Brake Valve Position | State | OR BrakeContoller Type |
|---|---|---|
| Release - OFF | The valve is closed, and the vacuum in the train pipe is held at value. Pipe leakage over time will reduce this value. | TrainBrakesControllerStraightBrakingReleaseOffStart |
| Release ON | The valve is opened, and air is allowed into train brake pipe to destroy the vacuum and release brake. | TrainBrakesControllerStraightBrakingReleaseOnStart |
| Application - OFF | The ejector is turned OFF when the desired level of vacuum is created in train brake pipe. | ORTSLargeEjector must be defined as an Engine Controller. |
| Application - ON | The ejector is used to create a vacuum in the train brake pipe, and thus applying the brakes. | ORTSLargeEjector must be defined as an Engine Controller to allow the ejector to be used. |
Timing Parameters
The above train brake uses the following timing parameters in the
Release - rate of release is the net sum of the following values = Large Ejector - Brake Pipe Loss. The rate of vacuum creation will be dependent upon the settings in the
Application - rate of application is based upon the ratio of
A working example configuration for this brake model can be found on the Stock Page
Hardy Non-Automatic (Straight) Vacuum Brake Controller - Single Ejector
This type of brake system controller was typically fitted to older steam locomotives, and used a single control valve.
Brake Valve Controller () (Train Brake)
| Brake Valve Position | State | OR BrakeContoller Type |
|---|---|---|
| Release | The valve is opened and air is allowed to enter the train pipe, this destroys the vacuum in the brake cylinders and releases the brakes. | TrainBrakesControllerStraightBrakingReleaseStart |
| Lap | The level of vacuum is held constant in train the brake pipe, apart from pipe leakage. | TrainBrakesControllerStraightBrakingLapStart |
| Application | The large ejector is used to create a vacuum in the train brake pipe, and thus applying the brakes to the locomotive and all cars. | TrainBrakesControllerStraightBrakingApplyAllStart |
Timing Parameters
The above train brake uses the following timing parameters in the
Release - rate of release is the net sum of the following values = Large Ejector - Brake Pipe Loss. The rate of vacuum creation will be dependent upon the settings in the
Application - rate of application is based upon the ratio of
A working example configuration for this brake model can be found on the Stock Page
Hardy Non-Automatic (Straight) Vacuum Brake Controller - Twin Ejector
This type of brake system controller was typically fitted to older steam locomotives, and used a single control valve.
Brake Valve Controller () (Train Brake)
| Brake Valve Position | State | OR BrakeContoller Type |
|---|---|---|
| Release | The valve is opened and air is allowed to enter the train pipe, this destroys the vacuum in the brake cylinders and releases the brakes. | TrainBrakesControllerStraightBrakingReleaseStart |
| Lap | The level of vacuum is held constant in train the brake pipe, apart from pipe leakage. | TrainBrakesControllerStraightBrakingLapStart |
| Application | The large ejector is used to create a vacuum in the train brake pipe, and thus applying the brakes to train cars only. | TrainBrakesControllerStraightBrakingApplyStart |
| Emergency | The large and small ejector is used to create a vacuum in the train brake pipe, and thus applying the brakes to the locomotive and all cars. | TrainBrakesControllerStraightBrakingEmergencyStart |
Timing Parameters
The above train brake uses the following timing parameters in the
Release - rate of release is the net sum of the following values = Large Ejector - Brake Pipe Loss. The rate of vacuum creation will be dependent upon the settings in the
Application - rate of application is based upon the ratio of
A working example configuration for this brake model can be found on the Stock Page
Brake Controller Code Format
The brake controller is defined with a range of positions that should match every position that the brake controller can be put into by the driver. It may have a smooth range of movement (ie graduated), notched movement or a combination of the two. The brake controller is defined by a block of code that has a typical format as follows:
ControllerName ( { min-val } { max-val } { step-val } { default-val }
NumNotches ( { n }
Notch ( { val } { smooth } { token-string } ) //one entry per notch
.................
)
)
The individual lines of code are explained as follows:
i) ControllerName ( { min-val } { max-val } { step-val } { default-val }Where -
ControllerName = name of the controller, for example it might be Brake_Train or Brake_Engine as appropriate
Min-val = minimum position of the controller, typically zero
Max-val = maximum position in the controller, typically one
Step-val = increment used when increasing /decreasing the control setting in OR for smooth ranges in notched controls, the smaller the number, the finer the adjustments in the control notch
Default-val = the position of the controller when OR starts, ie the brake can be ON, OFF, or in between.
ii) NumNotches ( { number }
Where -
Number = number of notches in the controller
iii) Notch ( { val } { smooth } { controller-token } )
Where -
Val = position between zero and one assigned to the notch
Smooth = allows smooth or notch movement, 0=notch, 1=smooth
Controller-token = the name of the brake token assigned to this notch. The token will assign relevant functionality or features to the notch position.
In particular, it is recommended that the "smooth" values not be set unless a continuous type brake token. Similarly attention should be paid to the "default-val" which will determine whether the position that the brake is in when OR starts.
For example, a typical train brake controller might look like the code block in the following section.
Sample Controller Code
The following example shows the typical controller for a Standard BR brake control valve.
Typically the lines shown in red text are the only ones that would need to be changed on individual wagons.
Comment ( *** Brake control equipment *** )
Brake_Train ( 0 1 0.3 0.4
NumNotches ( 4
Notch(0 0 TrainBrakesControllerReleaseStart )
Notch(0.3 0 TrainBrakesControllerRunningStart )
Notch(0.6 0 TrainBrakesControllerApplyStart )
Notch(0.9 0 TrainBrakesControllerEmergencyStart )
)
)
SmallEjectorOrCompressor ( 0 1 0.1 0.5 )
If an Independent Brake Valve Controller (Engine Brake) is required then the following code should also be added to this section of the ENG file. Leave code out if no Engine brake fitted.
Brake_Engine ( 0 1 0.4 0.5NumNotches ( 3
Notch(0 0 TrainBrakesControllerReleaseStart )
Notch(0.5 0 TrainBrakesControllerRunningStart )
Notch(0.9 0 TrainBrakesControllerApplyStart )
)
)
Useful Links
Handbook For Railway Steam Locomotive Enginemen - page 142 - Section 8 Brakes