Rapid "Twitching" between loco and coach

[J94Fan]

Hello

I've experienced a problem with "twitching" for some time . There is a visible (intermittant) twitching when I'm hauling Mk1 carriages! The front carriage vibrates rapidly, backwards and forwards, as if there is a problem with the buffer springs or coupling?

How can I fix this problem? It happens with more than one locomotive, so it must be the carriage (?). Here is the eng file code:

Code: Select all

Wagon ( Mk1BSKredandcream 
	Id ( ? )
	Type ( Carriage )
	WagonShape ( Mk1BSKredandcream.S )
	Size ( 2.74m 3.768m 20.2m )
	CentreOfGravity ( 0m 1.9m 0m )
	Mass ( 32t )
	InertiaTensor ( Box (2.7m 3.768m 20.2m) )
	Coupling (
		Type ( Automatic )
		Spring (
			Stiffness ( 1e6N/m 2e6N/m )
			Damping ( 1e6N/m 1e6N/m)
			Break ( 3.2e6N 3.2e6N )
			r0 ( 20cm 40cm )	
		)
		CouplingHasRigidConnection ( 1 )
		Velocity (0.1m/s)
	)
	Buffers (
		Spring (
			Stiffness ( 1e7N/m 0 )
			Damping ( 1e6N/m/s 0 )
			r0 ( 0m 1e9 )
		)
		Centre ( 0.5 )
		Radius ( 1 )
		Angle ( 0.5deg )

Thanks!

P.S. I loaded the eng file in Bounding Box Editor, but there were no errors.

[CaptainBazza]

The twitchiness is a known 'bug' in TS1, whether it's down to coupling types/settings I don't know, but a lot of time has been put into the question.

Cheers Bazza

[Lad491]

Ive got this at the moment in an activity im writing for TM where the tender is in a state of perpetual bounce against the loco I thought some time ago it was traced down to damping strength settings but I cant recall now. I can live with it though, even though the poor train crews must be being shaken to bits by such rough riding

[rlmathers]

Hi J94Fan

Try altering the Mk1BSKredandcream.wag to these parameters:

SIMISA@@@@@@@@@@JINX0D0t______

Wagon ( Mk1BSKredandcream
Id ( ? )
Type ( Carriage )
WagonShape ( Mk1BSKredandcream.S )
Size ( 2.74m 3.768m 20.2m )
CentreOfGravity ( 0m 1.9m 0m )
Mass ( 32t )
InertiaTensor ( Box (2.7m 3.768m 20.2m) )
Coupling (
Type ( Automatic )
Spring (
Stiffness ( 1e6N/m 2e6N/m )
Damping ( 1e6N/m/s 1e6N/m/s )
Break ( 3.2e6N 3.2e6N )
r0 ( 20cm 40cm )
)
)

CouplingHasRigidConnection ()
Velocity ( 0.1m/s )

Buffers (
Spring (
Stiffness ( 1e6N/m 5e6N/m )
Damping ( 1e6N/m/s 1e6N/m/s )
r0 ( 0cm 1e9 )
)
Centre ( 1.5 )
Radius ( 1 )
Angle ( 2.5deg )
)

The main changes are CouplingHasRigidConnection () and the Damping units should be N/m/s

Kindest regards
Ray

[J94Fan]

Hello again, ray

I'll give your parameters a go, and report back later!

[alanch]

All my mark 1's have these coupling and buffer settings, with no twitching. Two buffer statements are recommended, rather than the one that you have - this helps when you are coupling and uncoupling at either end.

Coupling (
Type ( Automatic )
Spring (
Stiffness ( 1e6N/m 5e6N/m )
Damping ( 1.3e6N/m/s 3.8e6N/m/s )
Break ( 5.4e7N 5.4e7N )
r0 ( 20cm 30cm )
)
CouplingHasRigidConnection ( 1 )
Velocity ( 0.12m/s )
)
Coupling (
Type ( Automatic )
Spring (
Stiffness ( 1e6N/m 5e6N/m )
Damping ( 1.3e6N/m/s 3.8e6N/m/s )
Break ( 5.4e7N 5.4e7N )
r0 ( 20cm 30cm )
)
CouplingHasRigidConnection ( 1 )
Velocity ( -0.12m/s )
)
Buffers (
Spring (
Stiffness ( 1e6N/m 5e6N/m )
Damping ( 1.3e6N/m/s 3.8e6N/m/s )
r0 ( 20cm 30cm )
)
Centre ( 0.5 )
Radius ( 1 )
Angle ( 0.5deg )
)

[J94Fan]

Thanks, Alan ... I'll try them later!

Ray's parameters didn't work, but thanks again for helping me!

[J94Fan]

Alan,

I've tried your "values", and it still twitched, albeit slightly differently (see below)

In my "enthusiasm" I forgot to mention that I'm using the front coupler i.e. tank engine facing backwards . The rear coupler seems fine.

Thank you for your efforts .... I assume that it's some kind of front coupler bug?

[alanch]

I have the latest version of the Bin patch installed, which might explain why I'm getting no twitching. Tell me which engine are you using, and I can give it a test - you could post the contents of the consist file here for me to try.

[systema]

It almost certainly has nothing to do with BIN.

The most likely cause apart from coupling settings is that your BBoxs are interfering with each other. Press cntrl and + on the numeric keypad, and you should see the bbox outlined in red. If the red boxes are too close they will cause much twitching. You will then have to change some values in wag and sd files. Are these standard downloaded units from UKTS?

Mick Clarke

[J94Fan]

Hello again ... here's the consist code:

Code: Select all

SIMISA@@@@@@@@@@JINX0D0t______

Train (
	TrainCfg ( "J94 + Mk1s (x4)"
		Serial ( 52 )
		MaxVelocity ( 31.29280 0.46372 )
		NextWagonUID ( 60 )
		Durability ( 1.00000 )
		Engine (
			Flip ( )
			UiD ( 59 )
			EngineData ( black#23 "WD191 Black" )
		)
		Wagon (
			WagonData ( Mk1BSKredandcream Mk1BSKredandcream )
			UiD ( 27 )
			Flip ( )
		)
		Wagon (
			WagonData ( Mk1SKredandcream Mk1SKredandcream )
			UiD ( 30 )
			Flip ( )
		)
		Wagon (
			WagonData ( Mk1TSOredandcream Mk1TSOredandcream )
			UiD ( 31 )
			Flip ( )
		)
		Wagon (
			WagonData ( Mk1FKredandcream Mk1FKredandcream )
			UiD ( 29 )
			Flip ( )
		)
	)
)

The loco is: File ID: 4497 Name:KESR #23 'WD191' '88-'89

I really appreciate your help

[J94Fan]

It almost certainly has nothing to do with BIN.

The most likely cause apart from coupling settings is that your BBoxs are interfering with each other. Press cntrl and + on the numeric keypad, and you should see the bbox outlined in red. If the red boxes are too close they will cause much twitching. You will then have to change some values in wag and sd files. Are these standard downloaded units from UKTS?

Mick Clarke

Hello

Yes, they are all standard units from UKTS, but I've modified them using "Bounding Box Editor" . I've checked the bounding boxes by pressing "ctrl" and "+", but none of the red lines are particularly close.

[systema]

What about between the loco and the first coach, and what are the bboxs like going around a curve. Have you checked the loco coupling statement?

You also should check the derailment properties in the wag and eng files.

Mick Clarke

[alanch]

I've had time to check out this consist, and I don't get any twitching. As I have edited the bounding box and couplings you might like to compare the first section of my engine file and its .sd file with yours:

SIMISA@@@@@@@@@@JINX0D0t______

Wagon ( black#23
comment( Austerity J94 by Paul Gausden (Decapod))
comment( Copyright 2002)
Type ( Engine )
WagonShape ( black#23.S )
Size ( 2.55m 3.75m 8.87m )
CentreOfGravity ( 0m 1.966011m 0m )
Centre ( 0m 0m 0m )
Mass ( 48.5t )

InertiaTensor ( Box ( 2.55m 3.75m 8.27m ) )
Coupling (
Type ( Automatic )
Spring (
Stiffness ( 1.2e6N/m 5e6N/m )
Damping ( 1.3e6N/m/s 3.8e6N/m/s )
Break ( 5.4e7N 5.4e7N )
r0 ( 2cm 5cm )
)
CouplingHasRigidConnection (1)
Velocity ( 0.2m/s )
)

Coupling (
Type ( Automatic )
Spring (
Stiffness ( 5e6N/m 1.2e6N/m )
Damping ( 3.8e6N/m/s 1.3e6N/m/s )
Break ( 5.4e7N 5.4e7N )
r0 ( 5cm 2cm )
)
CouplingHasRigidConnection (1)
Velocity ( -0.2m/s )
)
Buffers (
Spring (
Stiffness ( 9e6N/m 5e6N/m )
Damping ( 1e6N/m/s 1e6N/m/s )
r0 ( 0m 10cm )
)
Centre ( 0.5 )
Radius ( 1 )
Angle ( 0.5deg )
)


SIMISA@@@@@@@@@@JINX0t1t______

shape ( black#23.s
ESD_Detail_Level (0)
ESD_Software_DLev (0)
ESD_Alternative_Texture (0)
ESD_Bounding_Box ( -1.28 0.9 -4.13 1.28 3.75 4.14 )
)

And here is the first part of my version of the first coach with its .sd file:

SIMISA@@@@@@@@@@JINX0D0t______

Wagon ( Mk1BSKredandcream
Id ( ? )
Type ( Carriage )
WagonShape ( Mk1BSKredandcream.S )
Size ( 2.74m 3.89m 20.02m )
CentreOfGravity ( 0m 1.9m 0m )
Mass ( 32t )


InertiaTensor ( Box ( 2.74m 3.89m 19.42m ) )
Coupling (
Type ( Automatic )
Spring (
Stiffness ( 1e6N/m 5e6N/m )
Damping ( 1.3e6N/m/s 3.8e6N/m/s )
Break ( 5.4e7N 5.4e7N )
r0 ( 20cm 30cm )
)
CouplingHasRigidConnection ( 1 )
Velocity ( 0.12m/s )
)
Coupling (
Type ( Automatic )
Spring (
Stiffness ( 1e6N/m 5e6N/m )
Damping ( 1.3e6N/m/s 3.8e6N/m/s )
Break ( 5.4e7N 5.4e7N )
r0 ( 20cm 30cm )
)
CouplingHasRigidConnection ( 1 )
Velocity ( -0.12m/s )
)
Buffers (
Spring (
Stiffness ( 1e6N/m 5e6N/m )
Damping ( 1.3e6N/m/s 3.8e6N/m/s )
r0 ( 20cm 30cm )
)
Centre ( 0.5 )
Radius ( 1 )
Angle ( 0.5deg )
)


SIMISA@@@@@@@@@@JINX0t1t______

Shape ( Mk1BSKredandcream.s
ESD_Detail_Level ( 0 )
ESD_Software_DLev ( 3 )
ESD_Alternative_Texture ( 0 )
ESD_Bounding_Box ( -1.37 0.9 -9.7 1.37 3.89 9.72 )
)

[J94Fan]

Thank you for you time, Alan .... I'll test it later today!

(Oh, sorry for the delay in replying ..... there's an illness in my family)