A look at special cases of turnouts

Graeme Templer

Senior Associate,

Australasian Transport Risk Solutions (ATRS)

May 2013

Newcastle

• Grinding turnouts, when is it necessary?

• Effect of wheel profile

• Effect of hollow wheels

• Rail head shape when not ground

• Impacts and discontinuities

• Contact band and ARTC grinding standard

• Axle load distribution, histogram

• Fatigue failure of rail

• Effect of lubrication in turnouts

• Rail Seat Tolerances, re inventing the wheel

Questioning the Absolute Truths

Grinding turnouts when is it necessary

• Impacts

• Frederick’s 1968/74 at a bad fishplated joint, 10 x axle load at

rail surface

• Australian National Railways 1984/89 3x axle load at dipped

peaked or stepped weld

• Core 2002 5x axle loads in turnouts

• CRC AT9 2010 confirmed the above impacts in turnouts

IMPACTS

• The following contact stresses calculated from a computer

model

• Both wheel and rail profile

• Model Moves wheel from side to side to obtain maximum

contact stress

• Maximum allowable for Pt Kembla rail is 1035 Mpa otherwise

corrugations will develop

• 985 Mpa to less than 1035 mpa corrugations may develop

• Below 985 Mpa corrugations will not develop

• (BHP Melbourne research laboratories early 1980’s)

Rail stresses static condition no dynamics

New ANZR1 wheel on

R3 rail profile

Contact stress is

1231 MPa

(NCOP profile)

Average

worn ANZR

on R3 profile

contact

stress is

1154 MPa

Slightly worn

WPR2000 on R3

profile

Contact stress

2000 MPa

Average worn

WPR2000 on R3

profile

Contact stress

1328 MPa

Add Impact factor five times axle load

Contact stresses

• New ANZR1 on R3 contact stress is 6255 MPa

• Average worn ANZR1 on R3 contact stress is 5770 MPa

• Slightly worn WPR2000 on R3 profile is 10,000 MPa

• Average worn WPR2000 on R3 profile is 6640 MPa

• Contact stress for LWC to develop in 47kg,53kg rail ex Pt

Kembla is 1035 MPa

Current grinding profile for turnouts

50

40

30

20

10

0 -40 -30 -20 -10 0 10 20 30 40

45

Gauge Corner

C/L

~ 30-40 mm

Gauge Corner

Region

Field Side

Region Running Surface Region

Joints in T/O’s have not been straightened

• Narrow contact band, stresses well above 1035 Mpa

• A good strategy to trash the 47kg and 53 kg turnouts is to

grind a narrow profile on the rail where weld geometry in

turnouts has not been rectified.

• Do not grind without rectifying weld geometry

Why does the 47 kg Pt Kembla rail corrugate into 0.5

to 2m wavelength long wave corrugations? • Rail is a poorly designed section for bending

• Pt Kembla Rail has a low 0.2% FATIGUE failure yield stress

231 MPa

• Fracture mechanics by (BHP) MRL determined that at a

contact stress above 1035 MPa corrugations will develop

• Speeds and axle loads increased beyond 19 t at 90 KPH

• Currently 23 t at 80kph, 21 t at 115kph, locos 23t at 115kph

• It is the unsprung mass of the locos that cause the damage

• Rail fails in full section bending some plastic flow of the rail

surface

Curve 51kms North of Adelaide 19 November, 2009

CAT Trolley

1m to 1.5m corrugations in rail

Derrinallum, Western Line Victoria, 47 kg on Concrete, instantaneous values

greater than 0.3mm

Rail GTKs have an influence on residual life of 47kg

53kg rail• Western Victoria 300 MGT

• Vic Border to Adelaide 500 MGT

• Some sections of TAR 500 MGT

• Some sections of the TAR 200 MGT

• Coonamia to Broken Hill 150 MGT

• Melbourne to Albury 300 MGT

• Tottenham to Newport 500 MGT

• Victorian NE West track 50 MGT

• Southern NSW 53 kg rail 200 to 300 MGT

• Northern NSW 200 MGT maximum

Why grind the East West Nth Sth rail?

• To prevent corrugations forming

• Weld geometry in T/O’s has never been rectified

• Axle loads are such that normal surface defects shelling,

flaking spalling RCF does not develop.

• Grinding does not improve dipped weld geometry

• Grinding a narrow contact band increases contact stresses

with impact which ensures the corrugations will develop

faster

• Why grind?

The P1 gauge

MP12 grinders incapable of producing 0mm peak over 1m

Intermodal axle loads

From wayside Approximately 12 %

of axles are above

19 t those that do the damage to

the rail

Final Grinding: A reciprocating grinder. GOOD FINISH, REGULAR LATERAL PROFILE AND NO DIPS

Another type linear grinder

Good lateral profile as a bi-product

Weld shape effect• Effect of shape of weld

profile

• Next lot of slides

Dipped weld profile not improved by grinding

Weld pulls down with incorrect grinding technique

TR Weld 0010G018

217.5 km - Mar 2001

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

-500 -400 -300 -200 -100 0 100 200 300 400 500

Distance from Weld C/L (mm)

He

igh

t (m

m)

Coota to Parkes Weld profile after straightening

Coota to Parkes after straightening

Fatigue curves Stress versus cycles

Bending Stress Pt Kembla rail

Summary• If average axle loads are below 20 t. Ask the question why

are we grinding the turnouts

• If you decide to grind because it is nice to have then rectify

the welds first

• Grind off welds with a reciprocating linear grinder

• Throw out the P1 gauges

• Note turnout grinders do not grind pout long wave

corrugations in turnouts

• Long wave corrugations 0.5m to 2.0m primarily 0.7m

Wheel profile the WPR2000 wheel• Effect of introduction of the WPR2000 wheels to the

Interstate Network

The WPR2000, I in 10 conicity with a worn profile in the corner

The high conicity is designed to pull the high outer

wheel from the high rail and reduce wear of

both wheel and rail

The thickening of 7mm total in the gauge corner

gives the wheel more metal to wear

The 1 in 10 conicity allows this profile to go around

tighter curves than the ANZR1 profile without

wheel creep

Stability for wheels that end up with a lot of running on tangent tracks

Conicity of the WPR2000 Profile

0 20 40 60 80 100 120 140

-30

-20

-10

0

10

20

30

40

50

60

70

WPR2000 wheel profile

Millimetres

Mill

imetr

es o

r conic

ity 1

:n

WPR2000 shape

Conicity, 1:n

WRP2000 on un canted rail as per all of ARTC unground T/Os

except new Vossloh T/O

Contact Band through Points and unground crossings

Note at bottom and top through VEE

At sides on running rail WRP2000 on Gauge

Vee crossing up end Leeor Loop

Ararat mixed gauge diamond K crossing

Westmere Down End Vee crossing

Tattyoon up end vee crossing

Lubeck up end Vee crossing

Murtoa up end vee crossing

Murtoa down end vee crossing

Jung siding

Pimpinio vee crossing down end

Gerang Gerung down end vee crossing

New vee crossing at Stawell in service for two weeks

New vee crossing at Stawell

New vee crossings at Stawell

Vee crossings at Stawell

T/O at Musswellbrook

Note how wheels with high conicity cause abnormal wear

Recent order for turnouts had the same problem

• For a third time a new supplier delivered turnouts

not designed for the WPR2000 wheel still used in

the Hunter Valley

• Change of people and drawings not altered

• Wheel profiles must be given to supplier

Solution

Hollow wheels

• When the WPR2000

profile was introduced

no wheel condemning

gauge was introduced

to measure hollowing

• Wheel became more

hollowed that prior to

the WPR2000

introduction

• Effect of hollow wheelsEffect of wheel defects

Plastic failure in the gauge

corner creating untestable rail

Corrugations, Shelling,

Flaking, Squats, RCF

Hollow wheels Solution is to grind a

champher in the gauge corner

What is actually happening

• Grinding off the corner

creates high contact

stresses at the interface

pf corner grinding

• this leads to

accelerated RCF

• This generates more

grinding to remove the

RCF

• Solution new wheel

gauge developed and

hollowing defined fro

the WPR2000 wheel

Warp of the rail seats relative to each other

• This is a condition not understood in ARTC until relatively

recently

• However was a common problem in the heavy haul and

South Africa

• For twenty years there had been a truth it was caused by

peak and dipped welds

Mould numbers still visible

• Mould numbers are still

visible

• Sleepers that skew have

same mould numbers

Possible mechanism that causes skewing Rail seat Casting tolerances

Skew Sleepers TAR

Skew Sleepers TAR

Special pad to

prevent skewing

Mechanism of sleeper skewing• Identified in overseas railway in Pilbera in Australia

• Cause is warping of rail seats in longitudinal direction

• Moulds tolerance should be 1 in 400 on rail seat but some

moulds are 1 in 100

• Demonstrate with eraser

The longer rail span

• The longer span over skewed sleepers increases the rail

stress even further

• Fatigue life of rail is shorter than we think

Bending stress with skewed sleepers

• The bending stress with skewed sleepers is 60 % higher than

with regular spaced sleepers will have a significant impact

on rail fatigue life

Lesson for turnouts

• Rail seat tolerances must be 1 in 400 for rail seats in the

turnouts

• If this cannot be achieved then special anti skew pads

should be provided for turnouts

Heavy haul• Some examples in the Hunter Valley

• Kinematic Gauge Optimisation

• It’s a development from one of the suppliers, twice as expensive as

a normal turnout but they last at least 3 times as long

• They are shaped with a curve in turnout

Points 203• Hunter has installed 2 x KGO switches, 203a points has lasted 4

years, previous switch life was 12months.

• Also on at 142Pts installed Nov 2009, still OK, previous life 6

months

• The tangential switch assembly is an AS60Kg / AS68Kg ZU1-60 arrangement that has been

• manufactured to improve performance by incorporating Kinematic Gauge Optimisation or KGO

• In simple terms the switch and stock rail have been designed to assist the wheel in traversing the

• entry into the switch by controlling the wheel more effectively in both the straight and curving

• movements. The KGO design achieves this by bending the stockrails outwards by up to 15mm to

• achieve a varying rolling radius difference on the wheel. This widening of the stockrail at the entry

• of the switch also has the added advantage of increasing the thickness of the blade through the first

• 10 metres of the blade

Lubrication of Turnouts

Lubrication of turnouts

Lubricators not working

Lubricators not working

Flushing

QuestionsMoney