This document summarizes a study on developing an alternative to floating track slabs called a High Attenuation Sleeper track. It describes the objectives of developing a track that matches the vibration performance of floating slabs but with lower construction and maintenance costs. The chosen concept uses a mono-block resilient concrete sleeper with very soft pads. Laboratory and field tests showed the track met vibration targets. Initial cost estimates indicate it could provide up to 10% savings compared to floating slabs.

1. URBAN TRACK
Final Conference
Alternative to Floating Track Slab
High Attenuation Sleeper
Presented by Ian Robertson, ALSTOM
24 June 2010, Prague

2. Final Conference – 24 June 2010 2
Contents
Specific objectives of study
Chosen concept
Detailed design and laboratory test
Site test (ongoing)
Conclusions

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Specific objectives of study
 Develop slab track with following technical characteristics
 metro environment (18t axle load, 100 kph)
 equivalent vibration performance to Floating Slab Track
 ability to meet all railway constraints
 Safety (derailment) including track level evacuation
 Comfort
 maintenance
 Construction method
 for standard equipment and methods
 production rate as conventional track slab
 Lower costs compared to AFST
 For capital portion (design+procure+build)
 For maintenance portion

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Chosen concept
Review of existing systems worldwide
Previous generation bi-block sleepers for CTRL
 Relatively low weight
 Tie bar overstressed with very soft pads
 Track gauge variations with very soft pads
Chosen concept = mono-block resilient sleeper
High attenuation due to
 High sleeper mass (350 – 400 kg)
 Very soft resilient inserts (8KN/mm/fastener)
Adapted to tracklaying gantries
Maintenance friendly

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Detailed design and laboratory test
HAS mono-bloc sleeper concept
Rigid boot
Concrete
sleeperFastening
system
according
to
customer
choice
sealing
Holes for
conductor
rail
support

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Detailed design and laboratory test
Comparison of Different Antivibratile System
-60
-50
-40
-30
-20
-10
0
10
20 1
1,6
2,5
4
6,3
10
16
25
40
63
100
158
251
Frequency (Hz)
InsertionGain(dB)
Insertion Gain SFS 312 (dB)
Insertion Gain DFC Pandrol (dB)
Insertion Gain CTRL 2(dB)
Insertion Gain FST (Taipei) (dB)
Insertion Gain EGG_2(dB)
Insertion gain target

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Detailed design and laboratory test
DESIGN FULLY COMPLIANT WITH MOST RAIL FASTENERS
Typical tunnel layout

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Detailed design and laboratory test
Based on OBLEX project 20 cm gain
Dia.5.8 Dia. 5.6
Typical case of impact on tunnel diameter

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Detailed design and laboratory test
Time
Load 2 Hz
5 Hz
Fmax
.Fmax
Actual load diagram with sine shape
Optimum load diagram with triangle shape simulating wheel passage
Simplified load diagram used during fatigue test to simulate bogie passage
ACHIEVED 4,5 MILLIONS LOAD CYCLE WITH SUCCESS
HAS mono-bloc sleeper dynamic testing regime

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Detailed design and laboratory test
Mechanical test carried out
 Fatigue test with inclined loads according to the
following phases :
 1M Cycles @ low frequency (3 Hz) applied load between 10kN et
75kN, centred, inclined at 38°
 0.5MCycles @ moderate frequency (5 Hz) applied load between
30/40kN et 75kN centred , inclined at 38°
 2M Cycles @ low frequency (3 Hz) applied load between 10kN et
75kN, inclined at 10° and 38°
 1 M Cycles @ moderate frequency (5 Hz) applied load between
30/40kN et 75kN, inclined at 10° and 38°
NO PAD WEARING & NO VERTICAL STIFFNESS LOSS AFTER 4.5M
CYCLES
(EN13230: 2M CYCLES)

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Detailed design and laboratory test
EXCITATIO
N
MONOBLOC
SLEEPER
RAIL
RIGID
HULL
RAIL
PRELOAD
CONCRETE
BASE
SENSOR
S
Testing arrangements
Acoustic test
mechanical test

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Detailed design and laboratory test
0
2
4
6
8
10
12
MN/m
0 32 40 50 64
kN
Stifffness vs static load at 8Hz
K (MN/m)
Dynamic test results

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Site test (ongoing)
Several possibilities reviewed notably
 SINGAPORE Circle Line
 CEF test site (Valenciennes)
CEF chosen
 Easier logistics
 To respect URBAN TRACK timing
Construction just completed June 11
Vibration tests scheduled July
Introduction

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Site test - Situation
Test section
• 190m radius
• 160mm cant
Situation within CEF site
Actual track to replace
• ballasted track
• fishplated U50 rail
• good ground conditions
EV2 above 80 MPA

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Site test
 50m of High Attenuation Track
 2 x 6.5m of transition slab with ballasted track
 Sleeper spacing 700mm
 Welded rail on high attenuation zone
 Fishplated joints allowing movement at each end of test
General Layout

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Site test
Typical section

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Site test
Detailed design concept
230
230
80
2583
80200
Reinforced U-shaped foundation
Track « slab » concrete
 unreinforced
 With frequent joints to avoid shrinkage cracking

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Site test
After HAS vibration testing
 Axle load = 25 tonnes
 Total load = 280MGT
 HAS resilient inserts to replace by stiffer inserts
(30MN/M)
Structural design based on Eurocode 2
 Load Model 71
 Crack 0.2mm
Detailed design assumptions

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Site test
 Neighbouring (existing) ballast track
 Total dynamic stiffness around 80kN/mm per fastener
 High Attenuation Sleeper Track
 Under sleeper pad = 1,5*8 kN/mm
 Total stiffness = 11kN/mm per fastener
 Transition zone
 Target total stiffness = 46kN/mm
 Under sleeper pad = 70 to 80 kN/mm per fastener
 Total stiffness = 47 to 52 kN/mm per fastener
0.70.6 0.7
HAS
Track
Ballast
track
Transition zone
7
0.7
Transition slab design

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Site test
Construction after concreting of foundation

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Site test
Construction before track slab concreting

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Site test
In July testing of following zones
 HAS track
 Transition track
Static measurements
 Soil impedance
 Unloaded and loaded track impedance
 Determination of in situ HAS track characteristics
 Rail surface quality
Testing

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Site test
Dynamic measurements (6 pass-bys)
 train induced vibration levels
 on track slab concrete
 outside U shaped foundation
 rail and sleeper deflection of both rails
 rail and sleeper lateral displacements
Testing

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Site test
Strain measurements
 Captors on rail foot
 5 sleeper spacing per measurement site
Testing

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Site test
Vibration simulation
 HAS track parameters measured
 PACT reference track parameters
 Measured roughness
 Rolling Stock data
 Insertion gain calculation in 1/3rd octave bands
Testing

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Conclusions
 High performance alternative to floating track slab
 Ideal for underground metro applications
 Could absorb railway loads applied to sensitive bridges
 In high speed tunnel application
 Theoretically compared to “S3” high speed –4dB (halved the vibration level)
 Limiting operational criteria (mixed operations, speed, twist…) to determine
 Costing being completed but ballpark figures are
 Compared to typical metro floating track slab
 Design, procure and build cost HAS gives 10% saving
 Maintenance costs for HAS are much lower
 Potential to reduce tunnelling costs
 Further information
 final report will be ready after completion of CEF tests in August 2010
 See URBAN TRACK website http://www.urbantrack.eu/
 RGCF no 191 February 2010
 Railway Engineering 2009
High Attenuation Sleeper