Elvas Tower: Vacuum Braking Update - Elvas Tower

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Vacuum Braking Update Rate Topic: -----

#11 User is offline   steamer_ctn 

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Posted 17 November 2019 - 03:50 PM

To allow simple operation of some of the vacuum brake configurations, a simple control mode has been implemented. This will allow operation of the vacuum brakes without the need for the user to use all the ejector valves.

#12 User is online   darwins 

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Posted 14 January 2020 - 10:52 PM

It is now possible to have a separate large ejector on steam locomotives.

It is also now possible to have functional independent "steam brakes" on vacuum braked steam locos.
There is an example activity on the Coals to Newcastle website: https://www.coalstonewcastle.com.au/physics/demo-activity/#act7
The example is based on the Gresham & Craven type SSJ brake controller used on BR standard locos.

Thanks Peter for adding this to the OpenRails code.

This will allow more realistic braking control for BR, GWR, LMS and MR locos.

In the near future I will be releasing, via UKTS, some OpenRails updates to some of the excellent MSTS cab views by Hans Nooyen and Lew Price to include a large ejector control and high resolution gauges.

The details for this required in the eng section of the file are:
Comment ( ************************** Brake System *********************************************
Included in this section - Compressor, Reservoir, Application rates, etc
************************************************************************************* )

Comment (*** Braking systems ***)
BrakesTrainBrakeType( vacuum_single_pipe )
TrainPipeLeakRate ( 0.05inHg/s )

Comment (*** Ejectors ***)
Comment (* Estimate for Gresham & Craven SSJ type P ejector *)
VacuumBrakesHasVacuumPump ( 0 )
ORTSBrakePipeChargingRate ( 0.38inHg/s )
VacuumBrakesLargeEjectorUsageRate ( 690lb/hr )
VacuumBrakesSmallEjectorUsageRate ( 210lb/hr )
VacuumBrakesMinBoilerPressureMaxVacuum ( 110psi )

Comment (*** Brake Valve ***)
TrainBrakesControllerMaxSystemPressure ( 21InHg )
ORTSBrakePipeTimeFactor ( 0.02s )
ORTSBrakeServiceTimeFactor ( 10.0s )

Comment ( == Independent Brake valve - Engine & Tender == )
EngineBrakesControllerMaxReleaseRate ( 2.0inHg/s )
EngineBrakesControllerMaxApplicationRate ( 2.0inHg/s )

and in the EngineControllers section:
Comment ( Locomotive brake based upon Gresham & Craven MkIV Steam Brake Valve )
Brake_Engine ( 0 1 0.25 0.0
NumNotches( 5
Notch( 0 0 EngineBrakesControllerBrakeNotchStart )
Notch( 0.25 0 EngineBrakesControllerBrakeNotchStart )
Notch( 0.5 0 EngineBrakesControllerBrakeNotchStart )
Notch( 0.75 0 EngineBrakesControllerBrakeNotchStart )
Notch( 1 0 EngineBrakesControllerBrakeNotchStart ) ) )

Comment ( Based upon Gresham & Craven SSJ Ejector and control valve )
Brake_Train ( 0 1 0.1 0.1
NumNotches( 1
Notch( 0 1 TrainBrakesControllerVacuumContinuousServiceStart ) ) )

ORTSLargeEjector ( 0 1 0.1 0.0 NumNotches ( 0 ) )

ORTSSmallEjector ( 0 1 0.1 1.0 NumNotches ( 0 ) )








#13 User is online   darwins 

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Posted 21 January 2020 - 12:22 AM

There is now a second tutorial on the Coals to Newcastle website. This one uses a locomotive (LNER V2) with a combination ejector of the type that was common on the LNER, SR and many of the pre-grouping companies.

https://www.coalston...-activity/#act8

Another example will shortly be provided as a tutorial for GWR brakes.

The latest round of developments mean that brake valves in Open Rails now behave in a much more appropriate way for vacuum brakes.

These changes do not automatically work with old MSTS files, but a simple cut and paste can significantly improve the functionality of vacuum brakes in old MSTS steam locomotive models.

If you still wish to use MSTS as well as OR you will need to make a copy of the MSTS eng file and put it into an OpenRails sub folder.

Open the copy in the OpenRails sub folder and find the train brake part in the file - this is from the default Flying Scotsman

Brake_Train ( 0 1 0.01 0.65
NumNotches( 3
Notch(0 1 TrainBrakesControllerReleaseStart )
Notch(0.4 1 TrainBrakesControllerRunningStart )
Notch(0.5 1 TrainBrakesControllerApplyStart )
)
)


Replace the entire of the section with:

Brake_Train ( 0 1 0.2 0.2
NumNotches( 3
Notch( 0.0 0 TrainBrakesControllerReleaseStart )
Notch( 0.2 0 TrainBrakesControllerRunningStart )
Notch( 0.4 1 TrainBrakesControllerVacuumApplyContinuousServiceStart ) ) )


and you should find that vacuum brakes on your steam loco work in a similar way to how they used to work with MSTS and probably even better!

Any feedback on progress so far would be welcomed.

#14 User is online   darwins 

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Posted 22 January 2020 - 10:36 PM

The GWR demonstration is now available:

https://www.coalston...-activity/#act9

The demonstration uses a Hall class locomotive, with both large and small ejector controls as well as the driver's brake valve.

For those who like the GWR there it is now possible to include the brake controls as well as the vacuum pump for most types of GWR locos.

The same features will also allow improved brake models for MR/LMS and LNWR/LYR vacuum brake systems.

Together with the models above this gives fairly comprehensive coverage of vacuum brake systems for steam locomotives.

#15 User is offline   Traindude 

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Posted 22 March 2020 - 11:23 PM

View Postdarwins, on 21 January 2020 - 12:22 AM, said:


Open the copy in the OpenRails sub folder and find the train brake part in the file - this is from the default Flying Scotsman

Brake_Train ( 0 1 0.01 0.65
NumNotches( 3
Notch(0 1 TrainBrakesControllerReleaseStart )
Notch(0.4 1 TrainBrakesControllerRunningStart )
Notch(0.5 1 TrainBrakesControllerApplyStart )
)
)


Replace the entire of the section with:

Brake_Train ( 0 1 0.2 0.2
NumNotches( 3
Notch( 0.0 0 TrainBrakesControllerReleaseStart )
Notch( 0.2 0 TrainBrakesControllerRunningStart )
Notch( 0.4 1 TrainBrakesControllerVacuumApplyContinuousServiceStart ) ) )


and you should find that vacuum brakes on your steam loco work in a similar way to how they used to work with MSTS and probably even better!

Any feedback on progress so far would be welcomed.


I've been having trouble with the CTN test locos (such as the B1) with this brake script--even when I move the handle to the apply position, the brake pipe pressure doesn't decrease like it's supposed to, unless I open the end angle cocks from the F9 window. What am I doing wrong?

#16 User is online   darwins 

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Posted 22 March 2020 - 11:53 PM

Thanks. Will look again and report back. Does it work on MSTS locos at all (as opposed to CTN locos that may be set up with other OR values that conflict with this)?



#17 User is offline   Traindude 

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Posted 23 March 2020 - 12:32 AM

View Postdarwins, on 22 March 2020 - 11:53 PM, said:

Thanks. Will look again and report back. Does it work on MSTS locos at all (as opposed to CTN locos that may be set up with other OR values that conflict with this)?


I modified the default Scotsman to use the V2 brake script and it didn't work.

#18 User is online   darwins 

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Posted 23 March 2020 - 12:11 PM

Taking the case of the CTN B1 first of all - I can not reproduce the problem.
Firstly I downloaded the and installed the loco from the CTN website.
Secondly replaced the train brake part of the engine controller section with the one above.
This worked perfectly using OpenRails U2020.03.21-0706

Which version of OpenRails are you using?
You must be using a recent unstable version of OpenRails (released on or after the date of my post) for this controller to work.


Similarly I downloaded the latest version of the V2 from CTN website
Copied
Comment ( Based upon Davies & Metcalfe type VB ejector )
Brake_Train ( 0 1 0.2 0.2
NumNotches( 3
Notch( 0.0 0 TrainBrakesControllerReleaseStart )
Notch( 0.2 0 TrainBrakesControllerRunningStart )
Notch( 0.4 1 TrainBrakesControllerVacuumApplyContinuousServiceStart ) ) )

ORTSSmallEjector ( 0 1 0.1 0.55 NumNotches ( 0 ) )

Comment ( Locomotive brake - add for steam braked class V2 locos
Comment ( Engine brake should be omitted for vacuum braked V2 locos )
Brake_Engine ( 0 1 0.2 0.0
NumNotches( 1 )
Notch( 0 1 EngineBrakesControllerVacuumContinuousServiceStart ) ) )
and pasted into the default Scotsman and everything seems to work as it should.
You may need to send OpenRails Log files and copies of the eng files if you need me to investigate further.


#19 User is offline   Traindude 

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Posted 23 March 2020 - 04:33 PM

View Postdarwins, on 23 March 2020 - 12:11 PM, said:

Taking the case of the CTN B1 first of all - I can not reproduce the problem.
Firstly I downloaded the and installed the loco from the CTN website.
Secondly replaced the train brake part of the engine controller section with the one above.
This worked perfectly using OpenRails U2020.03.21-0706

Which version of OpenRails are you using?
You must be using a recent unstable version of OpenRails (released on or after the date of my post) for this controller to work.


Similarly I downloaded the latest version of the V2 from CTN website
Copied
Comment ( Based upon Davies & Metcalfe type VB ejector )
Brake_Train ( 0 1 0.2 0.2
NumNotches( 3
Notch( 0.0 0 TrainBrakesControllerReleaseStart )
Notch( 0.2 0 TrainBrakesControllerRunningStart )
Notch( 0.4 1 TrainBrakesControllerVacuumApplyContinuousServiceStart ) ) )

ORTSSmallEjector ( 0 1 0.1 0.55 NumNotches ( 0 ) )

Comment ( Locomotive brake - add for steam braked class V2 locos
Comment ( Engine brake should be omitted for vacuum braked V2 locos )
Brake_Engine ( 0 1 0.2 0.0
NumNotches( 1 )
Notch( 0 1 EngineBrakesControllerVacuumContinuousServiceStart ) ) )
and pasted into the default Scotsman and everything seems to work as it should.
You may need to send OpenRails Log files and copies of the eng files if you need me to investigate further.


I was using the stable version. I may try the unstable version to see how it works.

Update--it doesn't. I have attached the engine and log files to prove it.

#20 User is offline   vince 

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Posted 23 March 2020 - 07:57 PM

I don't know if this has anything to do with the bug but I see the coupler damping line is incorrect:
Damping ( 1e6N/m 1e6N/m )

It should be Damping ( 1e6N/m/s 1e6N/m/s ) as specified in the MSTS Tech Docs: Eng_and_wag_file_reference_guidev2.doc in the coupling section.
The above error is shown in the OpenRailsLog, fist two entries after the specs section.

The 'Match Braces' test in Context shows an anomaly also but I'm not sure how to interpret this.

regards,vince
edit:add info

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