RTSA
ALTERNATIVE TESTING METHOD FOR THE MEASUREMENT OF
BALLAST FOULING: PERCENTAGE VOID CONTAMINATION
Frank Feldman - Manager Ballast Cleaning and Formation, Program Maintenance Services, QR, Mackay
Darryl Nissen - Bachelor of Engineering Technology (Civil), Infrastructure North, QR, Rockhampton
SUMMARY
Economic constraints are driving the need for Queensland Rail (QR) to obtain more cost effective
maintenance methods such as better planning of proactive ballast-cleaning cycles. One means to achieve
this would be implementing testing methods that quantify the measurement of ballast fouling. Existing tests
do not realistically represent the extent of contamination. A contributing factor is that they are based on a
sieve analysis test that measures the mass of particles passing different sieve sizes. The Percentage Void
Contamination (PVC) is a volume based test, which measures the extent of void fouling for the depth of the
ballast profile, and takes into account the different densities of the contaminants.
This paper validates the PVC test by evaluating test results and comparing to existing test methods. The
PVC is a percentage value calculated by measuring the volume of contaminants (fouling material passing
9.5mm sieve) and dividing by the volume of voids within the existing ballast (retained on 9.5mm sieve).
Within QR's coal systems, it has been noted that most of the ballast fouling is due to coal infiltration and
ballast breakdown. The volume ratio range of contamination is in the order of 70% - 95% coal and 5% - 30%
ballast. Ballast cleaning is an efficient recycling maintenance activity used by QR to maximise ballast life and
decrease overall maintenance costs. However, as the extent of fouling is predominantly based on visual
inspections by track staff, ballast cleaning is not programmed as effectively as might be possible if it was
measured more quantitatively.
The volume of voids within new/clean ballast constitutes approximately 45% of the total volume of ballast
within track. As ballast becomes fouled its functions are minimised until the level of contamination reaches
the bottom side of the sleeper. At this stage ballast loses its resilience, void storage and drainage capabilities
and the total substructure then starts to fail. For minimal adverse effects on the superstructure, a minimum
live ballast depth of 100mm is required and the maximum limit of contamination should reflect this. When the
extent of fouling has reached this limit, the ballast cleaning process needs to be initiated to maximise the
cost effectiveness of track maintenance. Therefore the Percentage Void Contamination test needs to be
implemented in existing ballast cleaning procedures as a quantitative measure of ballast fouling.
101
Conference on Railway Engineering
Wollongong November 10-13 2002
& Darryl Nissen
Frank Feldman
Alternative Testing Method for the Measurement of
Queensland Rail
1
Ballast Fouling : Percentage Void Contamination
INTRODUCTION
indication of the percentage of void fouling. The
3
density of ballast ranges between 2500kg/m and
3
2800kg/m and the density of coal is between
3
3
800kg/m and 900kg/m . This means that coal
As stated by Selig and Waters' (1994), ballast is
a select crushed granular material placed below
and
around
the
sleepers
and
performs
the
fines for the same mass as ballast can occupy
following functions:
three times the voids
Resists vertical, lateral and longitudinal
•
forces applied to the sleepers to retain
remain
Provides some of the resiliency and
energy absorption for the track;
Facilitates maintenance surfacing and
and
thereby
reducing
its
of
the
misrepresentation
of
void
not frequently used to locate unacceptable fouled
ballast
rearrange ballast particles with tamping;
locations within
Inefficiencies
Provides immediate drainage of water
in
Infrastructure districts.
existing
test
methods
have
underlined the need for a simple test to measure
falling onto the track;
the percentage of void contamination for the
Reduces pressures from the sleeper
•
profile,
contamination, D-bar and Fouling Index tests are
lining operations by the ability to
•
saturated
Because
fouling material in the ballast;
•
ballast
bearing capacity.
Provides appropriate voids for storage of
•
the
ballast drainage also causes the formation to
track in its required position;
•
in
reducing drainage significantly. This reduction in
existing ballast profile. This report outlines this
bearing area to acceptable stress levels
new
for the underlying material.
procedure
and
compares
results
with
existing test methods.
In a newly constructed state, the volume of voids
within the ballast is approximately 45% of the
total volume of ballast within track. As ballast
becomes foul its functions are minimised until the
level of contamination reaches the bottom side of
the sleeper. At this stage the total substructure
starts to fail. Selig and Waters (1994) have stated
that ballast can become fouled from any of the
following sources:
•
Ballast breakdown;
•
Infiltration from ballast surface;
•
Concrete sleeper wear;
Infiltration
•
from
underlying
granular
layers;
Sub grade infiltration.
•
Within the coal systems of QR it has been noted
that
most
infiltration
of
the
and
ballast
ballast
fouling
is
breakdown.
by
coal
This
ratio
95% coal to 5% - 30% ballast.
Ballast
cleaning
is
an
SAMPLE LOCATIONS
2
range of contamination is in the order of 70% -
2.1
efficient
NORTH COAST LINE
recycling
maintenance activity used by QR to maximise
ballast life and decrease overall maintenance
costs.
Existing ballast cleaning programs are
formulated
by
canvassing
requirements
from
local Infrastructure Maintenance staff. The coal­
fouled locations are identified subjectively and
therefore not located or justified as consistently
as could be achieved by scientific means such as
material testing.
Existing ballast fouling test methods such as D­
bar and Fouling Index are determined from sieve
analysis and are based on mass. These tests do
not take into account the different densities of
contaminants and therefore do not give a true
Figure 2: Map showing Blackwater System
102
Conference on Railway Engineering
Wollongong November 10-13 2002
Frank Feldman
& Darryl Nissen
Alternative Testing Method for the Measurement of
Queensland Rail
Ballast Fouling: Percentage Void Contamination
Eight ballast samples were taken between Bajool
No
LOCATION
FOUL
CLEAN
and Archer on the North Coast Line on the down
SAMPLE
SAMPLE
track prior to undercutting. These eight locations
DATE
DATE
10/04/01
are listed below:
These samples were tested for sieve analysis
and percentage void contamination. Samples
were also taken at six locations, shown below,
after the Ballast-cleaning Machine (BCM) had
screened the contaminated ballast. This testing
was undertaken to ensure the efficiency of the
BCM.
No
LOCATION
.
FOUL
CLEAN
SAMPLE
SAMPLE
DATE
DATE
1
606.780kmDN
06/03/01
08/03/01
2
608.780kmDN
06/03/01
26/03/01
3
610.660kmDN
06/03/01
26/03/01
4
611.600kmDN
15/03/01
-
5
612.000kmDN
06/03/01
27/03/01
6
612.561kmDN
15/03/01
-
7
614.750kmDN
14/03/01
09/04/01
615.700kmDN
14/03/01
27/03/01
8
1
51. 226kmUP
09/04/01
2
52.050kmUP
09/04/01
10/04/01
3
53.122kmUP
09/04/01
10/04/01
4
54.000kmUP
09/04/01
10/04/01
5
60.305kmUP
19/04/01
20/04/01
6
61.000kmUP
09/04/01
20/04/01
7
77. 154kmDN
17/05/01
17/05/01
8
78.000kmDN
17/05/01
17/05/01
9
81.050kmDN
17/05/01
17/05/01
10
82.428kmDN
17/05/01
17/05/01
11
84.104km
29/05/01
29/05/01
12
103.011kmDN
23/04/01
09/05/01
13
103.011kmUP
23/04/01
30/04/01
14
113.659kmDN
09/05/01
09/05/01
15
114.482km
09/05/01
09/05/01
16
128.000km
09/05/01
17/05/01
Table 3: Sample locatIOns for Central lme
2.3
NEWLANDS BRANCH
Samples were taken and tested for sieve analysis
on
Table 1: Fouled & clean ballast sample
the
Newlands
Branch
No
Samples were taken and tested between Bajool -
LOCATION
Marmor at the following locations and dates:
No
.
LOCATION
141.000km
17/05/01
-
143.000km
17/05/01
-
2
DATE
DATE
596.418kmUP
07/06/01
-
2
597.399kmUP
07/06/01
-
3
598.402kmUP
07/06/01
-
4
601.740kmUP
29/05/01
-
5
602.769kmUP
29/05/01
-
CLEAN
SAMPLE
DATE
3
1
FOUL
SAMPLE
-
SAMPLE
SAMPLE
following
17/05/01
60. 000km
CLEAN
the
DATE
1
FOUL
at
locations and dates:
locations
Table 4: Sample locations on Newlands
branch
Table 2: Fouled ballast samples
2.2
CENTRAL LINE
Samples were taken and tested for sieve analysis
on the Central Line at the following locations and
dates:
Figure 3: Map showing Newlands Branch
103
Conference on Railway Engineering
Wollongong November 10-13 2002
Frank Feldman
& Darryl Nissen
Alternative Testing Method for the Measurement of
Queensland Rail
3
Ballast Fouling : Percentage Void Contamination
TESTING METHODOLOGY
ballast-cleaning strategies. The Percentage Void
Contamination is determined in a compacted
3.1
state to assimilate actual track conditions.
CURRENT TEST METHODS
There are currently two main methods for testing
3.2.2
the degree of fouling of ballast within the track,
Referenced documents
the D-bar and Fouling Index. Both methods are
AUST STD
calculated
AS1141
from sieve analysis and therefore
based on the mass of the ballast particles and
METHODS
Methods for sampling and
testing aggregates
contaminants.
AS1141.1
Method 1: Definitions
AS1141.2
D-bar
3.1.1
Method 2: Basic testing
equipment
AS1141.3.1
Method 3.1: Sampling
Aggregates
D-bar is a number that represents the weighted
geometric
average
of
particle
sizes
Table 5: Samplmg & testmg methods
passing
through grading sieves from a full sample. These
grading sieves are based on the QR ballast
3.2.3
specification. A new Grading A ballast has a
•
typical D-bar
=
36.60mm and ballast is deemed
Apparatus
A cylindrical water-tight measure made of
steel
to need replacement when D-bar ::; 10mm.
and
dimensions
conforming
-
251
to
capacity,
these
350mm
diameter and 250mm depth;
3.1.2
•
Fouling index
Metal
tamping
rod,
16mm
diameter,
600mm long with at least one tapered
Fouling Index is the summation of the percentage
end for a distance of 25mm to a spherical
fines passing the 4.75mm sieve and 75 microns
shape having a radius of 5mm;
sieve (FI =
P%4.75
+
P%
0075)'
fouling ranges for clean ballast (FI
The degree of
•
Balance or scale - ± 5g;
1%) to highly
•
Sample divider - AS 1141.2;
•
Scope or shovel.
<
fouled ( F I � 30%).
3.2.4
Test portions
A sample of ballast shall be obtained in
accordance with AS 1141.3.1. The location
of the selected sample is between the top of
sleeper
and
formation
level.
Divide
the
sample by sieving through a 9.5mm sieve.
3.2.5
Procedure
a) Sample retained on 9.5mm sieve
(ballast)
•
Test portion sufficient to overfill measure
•
Determine mass M1 of ballast retained on
•
Fill one third and compact 25 blows with
•
Repeat the above step until measure is full
•
Determine mass M1/1 of ballast in the
•
Fill with water and determine mass of
•
Calculate volume of voids V1
by 10% ;
9.5mm sieve;
ballast samples
3.2
tamping rod;
PERCENTAGE VOID CONTAMINATION
3.2.1
then level the surface;
measure;
Scope
The aim of this test method is to determine the
ballast and water M2;
percentage of void contamination of a ballast
sample taken from the total depth of the ballast
profile. This percentage value is calculated by
dividing
=
(M2-M1/1)
/ density of water.
b) Sample passing a 9.5mm sieve
the volume of contaminates by the
(contaminates)
volume of voids within the ballast profile. The
•
percentage of fouled voids indicates the lack of
Determine mass M3 of contaminates
passing a 9.5mm sieve;
drainage capabilities and loss of resilience of the
ballast. This ratio can be used to formulate
104
Conference on Railway Engineering
Wollongong November 10-13 2002
Frank Feldman
& Darryl Nissen
Alternative Testing Method for the Measurement of
Ballast Fouling : Percentage Void Contamination
Queensland Rail
•
particles must take place for the volume of
Calculate revised mass of
contaminants to be greater than the volume of
contaminates M3/1 =(M1 /1 xM3)/M 1 ;
•
voids.
Compact as above and determine
volume of contaminates (M3/1), V2.
The
Contamination from the following
strength
equation:
PVC
=
rate
of
return
is
also
affected
by
the
difference between the design ballast profile and
the existing ballast profile. In areas with low
c) Calculate Percentage Void
been
V2x100N1
soil formations,
significantly
ballast
increased
depths have
to
reduce
the
bearing pressures on the sub grade. By reducing
the ballast depth to the design, the rate of spoil
and rate of return are both maximised. Through
the cleaning process the screens may reject a
small quantity of useful ballast and this will
impact upon the rate of return. Therefore the
correct size, speed, throw, spacing, angle and
flow into the screens must be evaluated to fully
maximise the efficiency of the cleaning process.
A co-efficient of cleaning efficiency
(K)
can be
added to equation (1) to adjust for this variation.
\obI
r.1 "'lTf'ln II!d .11 ·lc.1'r.<1
(AQ,!) TI1JY,'!?pl); ..·:;u rre l: 4
In general, this co-efficient will have a value of
0.9
in
dry,
conditions
Figure 5: Shows volume of clean ballast &
slightly
but
fouled
depends
and
on
design
the
depth
factors
that
influence the rate of return.
voids versus volume of contaminants
Therefore for fouled ballast with PVC less than
3.3
100% the rate of return is outlined in equation (1)
RA TE OF RETURN
below:
The rate of return is the calculated percentage of
ballast returned to the track after the ballast
cleaning process has been completed.
Rate of Return
The rate
=
of return can be influenced by the following
factors:
•
Moisture content of the ballast;
•
The extent of contamination;
•
When the fouled ballast has PVC greater than
100% then the rate of return is shown in equation
(2):
Difference in depth of ballast profile from
design;
•
Rate of Return
Efficiency of the ballast-cleaning screens.
=
the
ballast
effectively
therefore
K x (volume of ballast +
(volume of ballast
When the ballast is saturated the screens cannot
clean
K x volume of existing ballast profile ..........(1)
total
3.4
renewal of the ballast profile may be the only
+
volume of voids)....(2)
volume of contaminants)
BALLAST LIFE PREDICTION
The Percentage Void contamination will give a
option. Theoretically, the volume of the ballast
quantitative measure of ballast fouling for the
profile should not change until the volume of
depth of the ballast profile.
contaminants is greater than the volume of voids.
Given this measure
of fouling, a limit of contamination, a time period
When this happens the rate of return is equal to
since undercutting and any changes in traffic
the volume of ballast plus the volume of voids
volume or type, a rate of contamination and a
divided by the volume of ballast plus volume of
ballast
contaminants.
life
or
ballast-cleaning
cycle
can
be
predicted for a track section or rail corridor. For
QR, the effect of ballast strength on ballast life
However as contaminants are concentrated at
has been significantly minimised due to the high
the bottom of the ballast profile through train
source material standards outlined in the QR
loading, resurfacing and rainfall, they may start to
Ballast Specification.
force the ballast particles apart even when the
volume of contaminants is less than the volume
Tests can be performed every two kilometres
of voids. Therefore even in this case there still
along a track section to calculate an average
may be a slight variation in ballast profile volume
PVC (PVCAVE) for any track section. A rate of
after cleaning. This pushing apart of ballast
contamination (ROC) can then be calculated by
105
Conference on Railway Engineering
Wollongong November 10-13 2002
Frank Feldman
& Darryl Nissen
Alternative Testing Method for the Measurement of
Ballast Fouling : Percentage Void Contamination
Queensland Rail
dividing the average PVC by the actual ballast life
which is the maximum recommended limit for the
(BLACT) since previous undercutting of the track
section.
indication of highly fouled ballast.
ROC (%/yr) = PVCAVE/BLA CT. . . . .. . . . . . . . . . . . . . ....(3)
4.2
PERCENTAGE VOID CONTAMINATION
The
test
This testing regime needs be completed in three
year cycles for coal lines and six year cycles for
for
the
Percentage
Void
These results show a comparison between PVC
freight lines to monitor the rate of contamination.
of contaminants passing the 4.75mm sieve and
This cycle of testing will ascertain if any changes
9. 5mm sieve, 9.5mm sieve and 19mm sieve and
in the rate of contamination are experienced.
19mm sieve and 26.5mm sieve. Testing was
Given that the ballast depth under the sleeper is
undertaken using the two sieve sizes to identify
250mm and the depth of crib ballast is 230mm,
contaminants
the maximum PVC at total fouling to the bottom
side of sleeper is approximately 50%.
results
Contamination (PVC) are listed in Appendix A.
in
order
to
achieve
a
better
comprehension of the relationship between the
If the
volume of voids and the volume of contaminants.
minimum depth of live ballast under the sleeper
for track stability is 100mm then the allowable
PVC limit to initiate ballast cleaning is reduced to
4.3
30%.
SIEVE ANALYSIS OF RECYCLED
BALLAST
Recycled ballast sampled from the BCM screens
at the locations shown in Appendix B indicates
that most particle size distributions are within the
specification for a Grading A ballast. Heavily
fouled
areas
show
that
screened
ballast
is
outside specification but still give a D-bar greater
than 26mm.
5
A
=
D-bar and the Fouling index are based on the
Depth of sooper
sieve
=
analysis
and
Figure
7
confirms
the
expected trend of D-bar decreasing and Fouling
B = Deplh of ballast
Umi of Contamination
DISCUSSION OF RESULTS
Index increasing.
IB-l001x IOO/IA B)
D-bar v's
Figure 6: Shows the PVC Limit of
Fouling Index
Contamination
The
allowable
ballast
life
(BLALd
or
�
ballast
cleaning cycle can be calculated by dividing the
Ql
4
4.1
PVCALL/ROC ......... . .. . . . .. .
0 0
+-------j
-g 20.0 +---���-----j
Cl 15.0 +-----I-"�----­
I:
"§ 10.0 +-----��._---.f 5.0 +------ln�'_F:--j
contamination for the track section.
=
+------:.---j
-; 25.0
allowable PVC limit (PVCALL) by the rate of
BLALL (yrs)
35.0 -.----.-:----,
30.0
. ... (4)
0.0 +----,-----,---j
0.00
10.00
20.00
30.00
40.00
RESULTS
D·bar (mm)
SIEVE ANALYSIS OF FOULED
Figure 7: Shows D-bar & Fouling Index
BALLAST
relationship
Appendix A shows that all of the sieve analyses
from the test sites are outside the particle size
The trend between % passing 26.5mm sieve and
distribution envelope outlined in the specification
the D-bar indicates that as % passing 26.5mm
for Grading A ballast. This grading limit failure
increases the D-bar decreases. However for a D­
bar of 20mm, % passing 26.5mm sieve ranges
indicates that all samples have some degree of
fouling. The D -bars are all greater than 10, which
have been the lower limit,
from 19 to 56. The trend shown in Figure 8 was
used for justifying
anticipated, when comparing a number of particle
cleaning. The Fouling Indices are all less than 30,
sizes to just one.
106
Conference on Railway Engineering
Wollongong November 10-13 2002
Frank Feldman
& Darryl Nissen
Alternative Testing Method for the Measurement of
Queensland Rail
Ballast Fouling : Percentage Void Contamination
% Passing
26.5mm v's D_bar
D·bar v's PVC
35.00
140.0.,------,
30.00
••
E 25.00
.§. 20.00
�
120.0 +---.....
�A
�� .
15.00
----j
-------
�.
C 10.00
�
�
.�.
•
ii:
o
.a
100.0 +-------j
80.0 +----r-----;---1
60.0 +-------.--,--1
40.0 +---�-A-....hr_
. --- ---j
....
20.0 +------.IoIr-r--...k---j
5.00
0.0 +----,-----,---j
0.00
o
20
40
0.00
80
60
10.00
% Passing 26.5mm
Figure 8: Shows
general,
% passing 26.5mm sieve &
Figure
9
shows
20.00
30.00
40.00
D·bar (mm)
Figure 10: Shows D-bar & PVC (9.5mm)
D-bar relationship
In
(9.5mm)
relationship
that
as
D-bar
Results in Appendix A show that two samples
with similar particle distribution, D-bar and
decreases the PVC increases. Figure 9 also
shows that for PVC (9.5mm) of 35%, the D-bar
Fouling Index, may have different PVC's by a
ranges from 15 to 25mm. This range difference is
factor of three. This indicates that the types of
significant and can be justified by the variation in
contaminates for the two samples are different
densities of the fouling material.
and this reflects in the make-up of their densities.
This means that one sample has a large amount
of broken down ballast in its fouling material while
D-bar v's PVC
�
;;
5:
400.0
350.0
300.0
250.0
200.0
150.0
100.0
50.0
0.0
the other may have a large amount of coal.
-.---�.-----,
+-----1
Results shown in Appendix B indicate recycled
ballast is returned to track with D-bars in the
+------=-.---l
range between 26 and 36mm.
+-------1
+-------'"'--1
+---..L...--e_-----I
+----=-==-=__------1
+-------r-....
clean ballast in the range of 26 to 29mm show up
to 37%
10.00
20.00
30.00
passing
26.5mm
sieve but only 2%
passing 9.5mm sieve.
+---,----,
0.00
These results
were foreseen, as the smallest screen on the
Ballast-cleaning Machine is 30mm. D-bars of
40.00
D·bar(mm)
.PVC (4.75mm)
• PVC (19mm)
a PVC (9.5mm)
I PVC (26.5mm)
Figure 9: Shows D-bar and PVC relationship
The PVC passing 9.5mm sieve gave a more
relevant perception of fouling as it compared
reasonably well with visual inspections. Selig and
Waters (1994) have previously validated that
material passing 9.5mm sieve are considered to
be contaminates. Results in Figure 10, which
show PVC above 100 %, indicate that the ballast
particles
have
been
forced
apart
by
contaminants. This may have occurred during the
continuous process of compaction from loads
and
vibration
from
traffic
and
resurfacing
operations.
107
Conference on Railway Engineering
Wollongong November 10-13 2002
Frank Feldman
& Darryl Nissen
Alternative Testing Method for the Measurement of
Ballast Fouling: Percentage Void Contamination
Queensland Rail
6
It is known that when fouling reaches the bottom
CONCLUSION
side of sleeper (PVC
The ballast sample was taken through the depth
of the total ballast profile. This gives a greater
starts to fail. Therefore the limit of contamination
perception of how much of the ballast is fouled.
must be less than 50%. Also the bottom side of
For example, if only the ballast below the bottom
sleepers will have much higher wear rate due to
increased attrition between foul ballast and
of sleeper is examined (sampled and tested) and
it shows total contamination, one might consider
sleeper. For minimal stability and operation of the
that it has just been reached in time. However, if
the
whole
profile
contamination
is
depth
is
tested
discovered then
and
one
50%, in concrete sleeper
=
track with 250mm of ballast) the substructure
superstructure,
75%
a
minimum
ballast
depth
of
100mm is required, reducing the allowable limit
could
for contamination or PVC to 30%. When the
conclude that the section should have been
and testing.
extent of fouling has reached this limit, the
ballast-cleaning process must be initiated to
The BCM returns clean ballast to the track in
maintenance. This allowable limit of PVC will
undercut several years prior to initial sampling
maximise
that
even
in
these
highly
a
sieve
realistic
and
relationship
actual
between
void
visual
contamination.
Sampling and testing should be completed every
inefficiently at these locations.
9.5mm
more
inspection
the BCM screener was processing fouled ballast
on
track
selection compared with other sieve sizes. It has
However D-bars below 30mm have a large %
passing 26.5mm sieve. It can be concluded that
PVC
of
The PVC on 9.5mm sieve is the most relevant
contaminated areas, D-bars are still above 26.
The
effectiveness
ballast depths.
any short falls are always in highly fouled areas.
show
cost
change for different track standards and different
most cases in near specification limits, however
Results
the
two kilometres in three year cycles for coal lines
gives
the
and six year cycles for freight lines to fully
best
comprehend
perception of fouling in the ballast. PVC of 50 %
the
rate
of
contamination
and
effectively predict ballast cleaning programmes.
shows that the contamination has reached the
bottom of sleeper and this compares reasonably
FUTURE DIRECTIONS
well with visual inspections in concrete sleeper
8
track with 250mm of ballast. Even though it must
Continuous
be taken into account from visual inspection,
analysis over time will result in actual rates of
data
collection,
correlation
and
contaminates in the top half of the fouled area
contamination.
are only loosely compacted and therefore this
limits will produce better ballast life predictions
ballast is still partially live. This is why PVC gives
thus
a more realistic
measures
the
resurfacing
perception of
compacted
fouling as it
volume
of
rates
contaminates. The assumption that material that
passes
the
9.5mm
sieve
are
defined
more
of
These
efficient
cycles.
return
will
rates
with
ballast
Further
result
appropriate
cleaning
investigation
in
more
and
into
efficient
utilisation of ballast contracts.
as
contaminates also agrees with Selig and Waters
(1994). The PVC is a more relevant than existing
test methods as it takes into account the different
densities of contaminates, being a volume-based
test.
Some results of PVC show a percentage greater
than 100. This implies that ballast particles must
have been forced apart by train traffic vibration,
resurfacing and rainfall. This mechanism starts at
an early
stage as contaminates migrate and
concentrate at the bottom of the ballast profile.
7
RECOMMENDATIONS
The Percentage Void Contamination test should
be implemented into existing ballast cleaning
procedures so that the amount and rate of ballast
fouling can be measured and proactive ballast­
cleaning cycles is better predicted.
108
Conference on Railway Engineering
Wollongong November 10-13 2002
Frank Feldman
& Darryl Nissen
Alternative Testing Method for the Measurement of
Queensland Rail
9
Ballast Fouling: Percentage Void Contamination
3. Jeffs, T, August 1994, Assessment of Ballast
REFERENCES
1. Selig, E.T. and Waters, J.M.,
Geotechnology
Management,
Telford
SeNices
Ltd,
4.
London.
Queensland
Rail,
BHP
QR
Civil
Engineering,
September
2000,
Railway Ballast Specification No. - CT.147A
2. Ravitharan, S.S.S, June 1996, Assessment of
5.
Ballast Perlormance for Queensland Rail Stage 2,
for
Research, Monash University, Melbourne.
Substructure
and
Thomas
Perlormance
1994, Track
BHP Research,
Monash
QR
Track
Maintenance
University,
Formation
Melbourne.
Engineering,
Guidelines
and
Drainage,
April
for
1999,
Ballast,
Workshop
Guide
Book.
109
Conference on Railway Engineering
Wollongong November 10-13 2002
Frank Feldman
& Darryl Nissen
Alternative Testing Method for the Measurement of Ballast Fouling
Percentage Void Contamination
Queensland Rail
APPEN DIX A
19mm
4.75mm
9.5mm
-
Sieve analysis and PVC test results
0.075mm
O_bar
LOCATION
63mm
53mm
37.5mm
26.5mm
Maximum
(Gradin!l A)
100
100
70
15
5
0.7
Minimum
(Grading A)
100
95
35
0
0
0
10.00
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
97
98
97
100
99
99
99
99
99
100
100
96
97
100
99
100
99
99
99
99
100
100
100
100
100
100
99
100
100
100
100
96
71
60
54
89
68
64
79
64
71
84
87
60
64
97
89
94
94
72
63
96
97
94
97
78
64
74
77
74
84
93
86
77
27
26
15
67
34
28
38
30
26
47
55
18
28
42
41
43
40
28
29
47
66
56
53
28
29
35
37
29
40
67
56
50
3
0.2
1.3
6.4
2.9
21.95
29.60
29.17
10.88
18.40
26.03
21.86
23.41
27.69
17.03
13.23
28.24
21.95
22.95
24.33
21.06
22.37
22.61
19.77
17.07
9.90
14.55
17.90
21.34
24.66
17.60
20.61
21.23
17.37
11.74
19.92
19.70
596.418U-NCL
597.399U
598.402U
601.740U
602.769U
606.7800
608.7800
610.6600
611.6300
612.0000
612.5610
614.7500
615.7000
51.226U-CL
52.050U
53.122U
54.000U
60.305U
61.000U
77.1540
78.0000
81.0500
82.4280
84.10470
103.0110
103.011U
113.6590
114.4820
128.000
60.000-NB
141.000
143.000
16
9.6
8.1
40
21
12
17
15
9.5
26
30
9.5
16
10
11
14
12
15
21
19
40
28
20
14
15
23
20
15
21
44
29
29
-
10
3.5
5.7
23
17
6.8
9.5
10
4.3
15
20
6.3
12
4.4
4
7.6
6.4
9.8
16
13
30
17
11
12
8.5
20
11
12
15
22
8
11
8.6
2.5
5.2
21
15
4.7
5.7
8.2
3.1
11
16
5
9.8
3.5
3
6.1
5.2
8.7
14
11
26
15
9.4
11
3
14
9
12
13
15
3.4
_ 5.�
_
1
1.3
1.6
0.5
2.6
5.3
0.9
2.5
1.5
0.9
1.8
1.4
2.1
2.4
3.5
6.6
3.8
2.4
2
1
1.5
2
2.3
3.4
3.9
0.6
1
Fouling Index
PVC (4.75mm)
PVC (9.5mm)
PVC (19mm)
13.0
32.7
20.0
122.5
72.2
23.2
173.2
79.4
PVC (26.5mm)
!
30.0
110
11.6
2.7
6.5
27.4
17.9
5.7
7.0
9.8
3.6
13.6
21.3
5.9
12.3
5.0
3.9
7.9
6.6
10.8
16.4
14.5
32.6
18.8
11.8
13.0
4.0
15.5
11.0
14.3
16.4
18.9
4.0
6.8
13.5
26.9
26.8
11.3
35.8
74.9
27.0
41.3
10.4
13.3
16.7
15.5
32.2
31.0
32.6
29.5
13.4
76.4
30.7
46.1
11.9
15.0
19.5
17.7
36.9
35.9
36.8
112.6
39.6
36.9
45.2
35.7
41.9
38.4
49.7
55.7
48.7
146.1
86.3
49.2
52.2
64.0
55.4
80.7
157.5
88.6
145.4
380.2
275.4
212.8
Conference on Railway Engineering
Wollongong November 10-13 2002
Frank Feldman
& Darryl Nissen
Alternative Testing Method for the Measurement of Ballast Fouling
Queensland Rail
Percentage Void Contamination
APPEN D IX B
LOCATION
-
Sieve analysis for cleaned ballast
63mm
53mm
37.5mm
26.5mm
O_bar
Fouling Index
100
98
53
7
0
0
36.60
0.0
Minimum
100
95
35
0
0
0
10.00
5
arget
19mm
9.5mm
4.75mm 0.075mm
Maximum
100
100
70
15
606.7800NCL
100
99
52
6.8
1
0.5
0.4
0.1
35.99
608.7800
100
96
44
7.4
1.4
0.7
0.7
0.3
36.72
1.0
610.6600
100
98
48
9.7
3.3
2.1
1.9
0.3
34.46
2.2
612.0000
100
96
59
14
3.9
2.2
1.8
1.6
31.20
3.4
614.7500
100
97
47
5.6
0.9
0.7
0.7
0.5
36.30
1.2
615.7000
100
96
52
12
2.8
1.4
1.1
0.2
34.57
1.3
51.226U-CL
100
100
79
20
3.2
1.1
1
0.5
30.11
1.5
52.050U
100
100
65
13
2
0.7
0.6
0.4
32.94
1.0
53.122U
100
100
80
18
1.6
0.6
0.6
0.4
30.87
1.0
54.000U
100
100
78
22
1.7
0.3
0.3
0
30.83
0.3
100
97
41
5
4
2.3
0.9
0.9
34.94
1.8
100
97
50
6
1.3
0
0
0
36.96
0.0
100
100
86
23
2.5
1.4
1.4
0.4
29.13
1.8
100
100
93
34
5.2
2.2
2.1
0.4
26.60
2.5
1.7
�0.350U
p1.000U
i77.1540
178.0000
�1.0500
0.7
30.0
0.5
100
100
92
34
5.5
1.6
1.4
0.3
27.07
82.4280
100
100
93
37
4.9
1.1
1
0.6
26.75
1.6
84.10470
100
100
60
9.7
2.5
1.2
0.9
0.1
33.85
1.0
103.011U
100
97
51
27
0.4
0.3
0.1
0
34.24
0.1
113.6590
100
100
50
6.2
0.8
0.4
0.4
0.2
36.20
0.6
114.4820
100
99
41
3.8
1.8
1.4
1.3
0.5
36.43
1.8
128.000
100
98
69
16
2.2
0.7
0.7
0.2
32.53 .
0.9
111
Conference on Railway Engineering
Wollongong November 10-13 2002