Brake Shoe Type

Hi All,

For several weeks now I have noticed the following Information Line with regard to BrakeShoeType being produced in the OR log.

Information: Unknown BrakeShoeType set to OR default (Cast Iron) with a MaxBrakeForce of 67.9 klbf

This presence of this line does not seem to affect the braking capabilities of stock.
A section of the OR log is shown below, the class 50 only being used as an example, the information line
appearing multiple times for all stock used in an activity.

Log

Information: Unknown BrakeShoeType set to OR default (Cast Iron) with a MaxBrakeForce of 67.9 klbf
Information:
================================================= DEE_50017
Information: Maximum Rail Output Power set by Diesel Traction Curves 2110 hp value
Information: Diesel Force Settings (ADVANCED Config): Max Starting Force 116.1 klbf, Calculated Max Continuous Force 33.7 klbf, @ speed of 23.5 mph
Information: Diesel Power Settings (ADVANCED Config): Prime Mover 2700 hp, Max Rail Output Power 2295 hp @ 850 rpm
Information: Slip control system: None, Traction motor type: DC
Information: Apparent (Design) Adhesion: Zero - 0.18 @ 0.0 mph, Max Continuous Speed - 0.13 @ 23.5 mph, Drive Wheel Weight - 257601 lb
Information: OR Calculated Adhesion Setting: Zero Speed - 0.33 @ 0.0 mph, Dropoff Speed - 0.31 @ 16.3 mph, Max Continuous Speed - 0.30 @ 23.5 mph
Information: ===================================================================================================================

The relevant section of the .eng file is written as follows:-

Wagon ( DEE_50017
BrakeEquipmentType ( Distributor, Auxilary_reservoir, Handbrake )
BrakeSystemType( Air_twin_pipe )
MaxBrakeForce ( 302kN ) Comment ( * braked @ 84.9%, coefficient of friction 0.31 *)
MaxHandbrakeForce ( 60kN )
EmergencyResVolumeMultiplier ( 1.0 )
MaxReleaseRate ( 0.44bar/s )
MaxApplicationRate ( 1.9bar/s )
MaxAuxilaryChargingRate ( 20.0 )
EmergencyResChargingRate ( 20.0 )
EmergencyResCapacity ( 2.064ft^3 )
BrakePipeVolume ( 1.46ft^3 )
ORTSNumberBrakeCylinders ( 2 )
ORTSBrakeCylinderSize ( 12in )
BrakeCylinderPressureForMaxBrakeBrakeForce ( 85psi )
ORTSBrakeShoeFriction
( 0 0.31 1 0.30 2 0.28 3 0.27 4 0.26 5 0.25 7 0.24 8 0.23 9 0.22 12 0.21 14 0.20 17 0.19 20 0.18 24 0.17 29 0.16 34 0.15 40 0.14 47 0.13 55 0.12 66 0.11 84 0.10 115 0.09 160 0.09 )
Comment ( cast iron brake shoes )

In the OR manual the command line set up is shown as follows:-

To setup the WAG file, the following values need to be set: •
OR parameter ORTSBrakeShoeFriction ( x, y )
to define an appropriate friction/speed curve, where x = speed in kph, and y = brakeshoe friction. This parameter needs to be included in the WAG file near the section defining the brakes. This parameter allows the user to customise to any brake type. • Define the MaxBrakeForce value with a friction value equal to the zero speed value of the above curve, i.e. in the case of the curve below this would be 0.49. For example, a sample curve definition for a COBRA (COmposition BRAkes) brakeshoe might be as fol lows:
ORTSBrakeShoeFriction ( 0.0 0.49 8.0 ................ 80.5 0.298 88.5 0.295 96.6 0.289 104.6 0.288 ) The debug FORCES INFORMATION HUD has been modified by the addition of two extra columns.

As far as I can understand my .eng file (wagon section) is set up correctly ie

ORTSBrakeShoeFriction
( 0 0.31 1 0.30 2 0.28 3 0.27 4 0.26 5 0.25 7 0.24 8 0.23 9 0.22 12 0.21 14 0.20 17 0.19 20 0.18 24 0.17 29 0.16 34 0.15 40 0.14 47 0.13 55 0.12 66 0.11 84 0.10 115 0.09 160 0.09 )
Comment ( cast iron brake shoes )

And so my Question is ………..can anyone explain why the information line
Information: Unknown BrakeShoeType set to OR default (Cast Iron) with a MaxBrakeForce of 67.9 klbf
Is being generated in the log file???

Some data from log file that may be relevant.
Version = U2023.06.21-0952
Build = 0.0.8572.17973 (2023-06-21 09:59:06Z)
SimpleControlPhysics = False
ActRandomizationLevel = 0
ActWeatherRandomizationLevel = 0
AdhesionFactor = (user set) 67
AdhesionFactorChange = 10
AdhesionMovingAverageFilterSize = 10
AdhesionProportionalToWeather = (user set) True

Any ideas or views on the above would be most welcome

Cheers

Terry White

Hi Again Everyone,

The issue described in my previous post earlier today can be resolved as shown below.

NEW LINE ADDED ORTSBrakeShoeType ( "Cast_Iron" )

THIS LINE CHANGED FROM
MaxBrakeForce ( 302kN ) Comment ( * braked @ 84.9%, coefficient of friction 0.31 *)
TO
ORTSMaxBrakeShoeForce ( 302kN ) Comment ( * braked @ 84.9%, coefficient of friction 0.31 *)


BrakeEquipmentType ( Distributor, Auxilary_reservoir, Handbrake )
BrakeSystemType( Air_twin_pipe )
ORTSBrakeShoeType ( "Cast_Iron" )
ORTSMaxBrakeShoeForce ( 302kN ) Comment ( * braked @ 84.9%, coefficient of friction 0.31 *)
MaxHandbrakeForce ( 60kN )
EmergencyResVolumeMultiplier ( 1.0 )
MaxReleaseRate ( 0.44bar/s )
MaxApplicationRate ( 1.9bar/s )
MaxAuxilaryChargingRate ( 20.0 )
EmergencyResChargingRate ( 20.0 )
EmergencyResCapacity ( 2.064ft^3 )
BrakePipeVolume ( 1.46ft^3 )
ORTSNumberBrakeCylinders ( 2 )
ORTSBrakeCylinderSize ( 12in )
BrakeCylinderPressureForMaxBrakeBrakeForce ( 85psi )
ORTSBrakeShoeFriction
( 0 0.31 1 0.30 2 0.28 3 0.27 4 0.26 5 0.25 7 0.24 8 0.23 9 0.22 12 0.21 14 0.20 17 0.19 20 0.18 24 0.17 29 0.16 34 0.15 40 0.14 47 0.13 55 0.12 66 0.11 84 0.10 115 0.09 160 0.09 )
Comment ( cast iron brake shoes )

The Log now shows this:-
Information: Number of Locomotive Brakeshoes set to default value of 24
Information:
================================================= DEE_50017 =================================================
Information: Maximum Rail Output Power set by Diesel Traction Curves 2110 hp value
Information: Diesel Force Settings (ADVANCED Config): Max Starting Force 116.1 klbf, Calculated Max Continuous Force 33.7 klbf, @ speed of 23.5 mph
Information: Diesel Power Settings (ADVANCED Config): Prime Mover 2700 hp, Max Rail Output Power 2295 hp @ 850 rpm
Information: Slip control system: None, Traction motor type: DC
Information: Apparent (Design) Adhesion: Zero - 0.18 @ 0.0 mph, Max Continuous Speed - 0.13 @ 23.5 mph, Drive Wheel Weight - 257601 lb
Information: OR Calculated Adhesion Setting: Zero Speed - 0.33 @ 0.0 mph, Dropoff Speed - 0.31 @ 16.3 mph, Max Continuous Speed - 0.30 @ 23.5 mph
Information: ===================================================================================================================
Information: Number of Wagon Brakeshoes set to default value of 8
Information: Number of Wagon Brakeshoes set to default value of 8
Information: Number of Wagon Brakeshoes set to default value of 8

The three lines at the bottom of the log refer to the wagons of the consist

Cheers again

Terry

This is a new feature in development. As you said there should be no change to existing performance. As set up now it should make it easier to enter data for US and historic UK rolling stock and get better results.
So if we look at the class 50 diagram it says weight in working order is 151 tons 1 cwt = 338,532lb
Also brake force as % of loco weight in working order is 84.9% which is = 287,260lbf.
We can now enter this directly into OR as ORTSMaxBrakeShoeForce ( 287260lbf )
The class 50 Co-Co has six axles, 12 wheels, all braked with two braked shoes on each wheel, which gives ORTSNumberCarBrakeShoes ( 24 )

The max brake cylinder pressure on the class 50 was 85 psi - so far as I am aware the highest on any BR diesel or electric loco. This can now be achieved using another new OR feature ORTSBrakeRelayValveRatio ( 1.64 )
The 1.64 in this case is the number you need to multiply the default brake cylinder pressure by to get the actual brake cylinder pressure. (Many other diesels had 70psi or 60psi).

Another new term, ORTSBrakeCylinderVolume ( ) can now be used a single line to replace all of:

EmergencyResVolumeMultiplier               ( 1.0 )
EmergencyResChargingRate                   ( 20.0 )
EmergencyResCapacity                       ( 2.064ft^3 )

ORTSBrakeShoeFriction ( 0 0.31 1 0.30 2 0.28 3 0.27 4 0.26 5 0.25 7 0.24 8 0.23 9 0.22 12 0.21 14 0.20 17 0.19 20 0.18 24 0.17 29 0.16 34 0.15 40 0.14 47 0.13 55 0.12 66 0.11 84 0.10 115 0.09 160 0.09 ) Comment ( cast iron brake shoes )
is no longer needed and can be replaced with ORTSBrakeShoeType ( "Cast_Iron" ) other types will be made available shortly.

So an updated entry for the class 50 would look like this:

BrakeEquipmentType ( Distributor, Auxilary_reservoir, Handbrake )
BrakeSystemType( Air_twin_pipe )
TripleValveRatio( 2.5 )

ORTSBrakeShoeType ( "Cast_Iron" )
ORTSMaxBrakeShoeForce ( 287260lbf ) Comment ( * braked @ 84.9% *)
ORTSNumberCarBrakeShoes ( 24 )

ORTSBrakeCylinderVolume ( 1.0ft^3 ) Comment ( * guess * )

MaxHandbrakeForce ( 60kN )

MaxReleaseRate ( 0.44bar/s )
MaxApplicationRate ( 1.9bar/s )
MaxAuxilaryChargingRate( 0.40bar/s ) Comment ( >0.85 * MaxReleaseRate )

BrakePipeVolume ( 1.46ft^3 )

BrakeCylinderPressureForMaxBrakeBrakeForce ( 85psi )
ORTSBrakeRelayValveRatio ( 1.64 )


As work is still in progress, I will give an update later. I am not too sure of the correct values for ORTSBrakeCylinderVolume ( ) in this case, as I do not know the brake cylinder sizes on this loco.

There are also changes being made so that not all wheels need to be braked, for example on steam locos and class 45 diesels only the driving wheels are braked.

Hi Darwin

And thanks for the update on the work in progress with regard to brake parameters and data.

I will endeavour to use your data and update the class 50 .eng file. I will attempt to update some other classes in due course.

It would be useful to have an update on WIP at a later date. In the meantime I think I will have to check on the CTN site more frequently to see if any changes have been made on the sample pages. That was where I picked up on the addition of the two parameters that resolved the issue that started this thread.

All the best for now

Terry

Sorry, not quite up to date. Please use ORTSBrakeShoeType ( "Cast_Iron_P10" ) for class 50 and most modern diesel and electric locos.
For older rolling stock including steam locos use ORTSBrakeShoeType ( "Cast_Iron_P6" )

Oh Ok!

Does that mean that there is potentialy going to be a table of various values produced to suit that particular parameter??..... or is that information available on line?

When you say table, do you mean like ORTSBrakeShoeFriction ( x1 y1 x2 y2... )?

If so that is no longer needed. New unstable versions of OR have four built in tables that will cover most possibilities. These now include the effects of pressure as well as the effects of speed!

ORTSBrakeShoeType ( "Cast_Iron_P6" ) - Use for all older rolling stock with cast iron brake blocks. (Most steam era, early BR, and motor cars on Southern Railway emu sets).

ORTSBrakeShoeType ( "Cast_Iron_P10" ) - Use for modern era rolling stock with cast iron brake blocks. Also for low friction composite materials used to replace cast iron. (For example early BR emu trains and trailer cars on SR emu sets).

ORTSBrakeShoeType ( "High_Friction_Composite" ) - For some modern US locos and European rolling stock, not widely used in UK, may be on some modern goods wagons. (May be use for HST power cars that have a combination of both disc brakes and brake shoes.)

ORTSBrakeShoeType ( "Disc_Pads" ) - Modern era passenger cars (most Mk3 and after) and multiple unit trains. (Gives a nominal coefficient of friction of 0.35 so good approximation for UIC standard disc brakes.)

plus

ORTSBrakeShoeType ( "User_Defined" ) - allows you to enter your own table of ORTSBrakeShoeFriction ( x1 y1 x2 y2... ). Use this option if you want either very old wooden brake blocks or a very specific disc brake material.

"When you say table, do you mean like ORTSBrakeShoeFriction ( x1 y1 x2 y2... )?"

Sorry for my unclear question.

No, I ment a table/List of data in the same way as how you replied in your last post. I had a feeling that there might be more than two values and wondered what the other values and applications might be if indeed there were more.

Your reply answered all, so many thanks for that.

Cheers again

TW