Suggestions for Efficient Measures
Short and Medium term
Gavin Astin
29 September 2011
Agenda
1. Background
2. Quantitative
Assessment
3. Qualitative
Assessment
4. Conclusions
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Next Step – Efficient Measures
 Is the benefit secured (avoided derailments) worth the investment?
 An investment made will return benefits over the lifetime of the measure. Economic
indicators used:
- Net Present Value – the difference between the present value of cash inflows and the
present value of cash outflows.
- Benefit / Cost Ratio – the ratio of benefits to costs (a ratio greater than 1 indicates that the
benefit outweighs the cost).
- Internal Rate of Return - can be defined as the break-even interest rate which equates the
Net Present of a projects cash flow in and out.
 It is the consideration of these factors that lead to our assessment of those
measures that are the most efficient.
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Agenda
1. Background
2. Quantitative
Assessment
3. Qualitative
Assessment
4. Conclusions
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Potential Benefits
Measure
P1-Check Rail
P2-Track Lubrication
P10&12-HABD/HWD
P11-BAM
P13-WLID/WIM
P15-Bogie Hunting Detector
P16-Wheel Profile
P18-Track Geometry
P19-Clearance Flange Groove
P28-Roller Cages
F6-Anti Lock Device
F7-Sliding Wheel Detector
M1a-Derail Det All Freight
M1a-Derail Det All DG
M1a-Derail Det RID
Avoided
Avoided Track
Fatalities
Damage (km)
0.16
35
0.09
20
0.47
70
0.41
63
0.59
104
0.29
63
0.14
30
0.36
85
0.04
6
0.29
44
0.17
28
0.06
10
0.96
0.85
0.12
Annual Benefits
Avoided
Avoided
Avoided Wagon
Operation
Environmental
Damage (number) Disruption (hrs)
Events
109
751
3
61
422
2
270
1889
8
240
1673
7
366
2542
10
199
1377
5
95
657
2
280
1941
7
23
164
1
169
1180
6
99
693
3
35
241
1
341
45
9
379
50
10
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2881
380
76
17
4
1
Derails
prevented
23
13
53
47
74
42
20
58
4.5
33
20
7
Severe
derailments
saved
76
10
2
Quantitative Assessment
Net Present Values
Rank Measure
1 P13-WLID/WIM
2 P28-Roller Cages
3 P15 Bogie Hunting Detector
4 P11-BAM
5 F7-Sliding Wheel Detector
6 M1a-Derail Det RID
7 P16-Wheel Profile
8 M1a-Derail Det All DG
9 M1a-Derail Det All Freight
10 P10&12-HABD/HWD
11 P19-Clearance Flange Groove
12 P18-Track Geometry
13 P1-Check Rail
14 P2-Track Lubrication
15 F6-Anti Lock Device
Benefit / Cost Ratio
Internal Rate of Return
10 years 20 years 40 years 10 Years 20 Years 40 Years 10 years 20 years 40 years
379
109
80
47
-0
-2
-27
-44
-385
-507
-20
-373
-701
-276
-3,581
756
284
283
294
35
17
65
56
303
-257
-34
-568
-635
-459
-3,581
1,183
482
514
572
75
39
170
170
1,094
27
-49
-788
-559
-667
-3,580
3.1
1.7
1.4
1.1
1.0
0.9
0.8
0.8
0.7
0.5
0.6
0.5
0.2
0.3
0.0
5.1
2.9
2.2
1.9
1.6
1.5
1.4
1.3
1.2
0.7
0.6
0.6
0.3
0.3
0.1
7.4
51%
52%
52%
4.2
16%
21%
21%
3.2
8%
14%
15%
2.8
3%
10%
11%
2.4
0%
7%
9%
2.2
-2%
6%
8%
1.9
-4%
5%
7%
1.8
-6%
3%
6%
1.7
-7%
3%
5%
1.0
-16%
-4%
0%
0.6
N/A
N/A
N/A
0.6
N/A
N/A
N/A
0.4
-31%
-14%
-6%
0.3
N/A
N/A
N/A
0.1
N/A
N/A
N/A
Benefit
74 AD
33 AD
42 AD
47 AD
7 AD
2 AS
20 AD
10 AS
76 AS
53 AD
4.5 AD
58 AD
23 AD
13 AD
20 AD
 Based on our assessment of available benefit versus cost to secure that benefit at
20 years.
 AD = Avoided Derailment; AS = Avoided Severe Derailment (prevents an initially non
severe derailment from escalating in consequence).
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Discussion – Preventative Measures
 P10 & P 12 - HABD / HWD:
- Extensively applied already, current devices being updated, new devices being installed.
- Benefit reducing for this reason.
- High installation density required.
 P28 - Roller Cages:
- Our assessment is for replacement of existing roller cages as soon as possible, an
alternative measure is for replacement at next maintenance interval.
 P11 – BAM:
- Installation of bearing acoustic monitors along the track that might be an alternative to hot
axle box detectors as less detectors are necessary. Networking of information might be
required.
 P13 – WLID:
- Wheel load and wheel impact load detectors have a broad functionality in terms of detecting
overloading, skew loading, wheel damage and out of roundness which leads to HABD.
 A lot of measures directed towards the same cause (hot axle box), but more than
80% of derailments are from causes other than hot axle boxes.
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Discussion – Mitigation Measures (with automatic brake
application) versus Prevention
 Consider measure M1 applied to all Freight trains (M1a-Derail All Freight) and P13WLID/WIM detectors.
 We can see that M1a-Derail Det All Freight prevents 76 derailments from becoming
severe whilst P13 prevents 74 derailments from occurring at all.
 On first consideration it may seem that preventing 74 derailments is the better
outcome. However of these 74 a number will be safely managed (if occurred) and
would not escalate in consequence, therefore only a proportion of these prevented
derailments are severe (if occurred).
 We will see later that M1a has drawbacks which have not been discounted from the
benefits. Also the cost of implementing measure M1a means it is less cost effective
than P13.
 We note an alternative type of derailment detection device which provides an alarm
to the train driver when a derailment is suspected, but without an automatic brake
application (type M1b). We are not aware of these being available on the market
(for freight application) in Europe. Consideration of these devices, the human
factors issues involved and their costs would be required prior to formal assessment
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Drawbacks
 False alarms are possible with most of these measures, although an appropriate
monitoring alarm management regime can minimise these.
 Item M1 (derailment detection with automatic brake application) could provoke a
derailment in false alarm cases.
 Measure F7 – Sliding Wheel Detectors are not known to have many suppliers.
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Agenda
1. Background
2. Quantitative
Assessment
3. Qualitative
Assessment
4. Conclusions
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Organisational and Other Options
 A lot of our measures could be considered to be replacements or substitutes for
proper organisational controls. What other options are there?:
 Loading errors can contribute significantly to freight train derailments, usually in
combination with other defects like poor train handling / adverse track geometry.
- It could be considered to require the qualification and registration of loading personnel.
 Track geometry issues, particularly those attributable to track twist, are a major
concern. We estimated between 34 and 50 per annum; these include cases where
track twist is within existing safety limits, but due to unfortunate freight train
composition and loading (which may also be within relevant criteria) combine to
cause a derailment:
- A system of common and stricter safety limits and intervention limits could be a step forward.
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Present Obligations
 Existing Safety Management Systems should address:
- Poor maintenance standards of rolling stock can lead to derailments (including many simple
and routine tasks).
- Failure to maintain track geometry and other asset conditions – particularly in secondary and
side-tracks – is a common cause of derailments.
 Increased supervision of these parameters by NSAs or other independent parties
could be an effective control
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Agenda
1. Background
2. Quantitative
Assessment
3. Qualitative
Assessment
4. Conclusions
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Background and Context
 We have looked at the potential for improvement, and not an absolute
assessment of the efficiency of all measures that are applied today. Therefore it
follows that if a measure is applied extensively already there is little room for
improvement through the further application of that measure. For this reason some
measures that are extensively applied already are not considered in this work. Their
omission should not be considered as suggesting such measures are not efficient.
 The assessment of measures does not consider the way or the order in which these
interventions should be pursued, for example it is not considered whether these
interventions should be introduced in a mandatory or voluntary way or whether the
measure should be introduced as an EU harmonised measures or only within
certain member states or only certain companies.
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Efficient Measures (1 to 5)
 We consider the following technical measures as being efficient (they have a
positive or unity benefit / cost ratio in our reference case and all sensitivity studies):
-
P13-Wheel Load Impact Detectors / Weighing In Motion.
P28-Replacement of Brass for Polyamide Roller Cages.
P15-Bogie Hunting Detectors.
P11-Bearing Acoustic Monitoring.
 Considering measure P28, we have considered an immediate replacement of
brass/steel for polyamide roller cages. An alternative option is for replacement at
the next scheduled maintenance interval for bearings/axle boxes. This is almost a
zero cost option, although the benefits would take longer to materialise.
 Potential drawbacks to the use of these measures (excluding measure P28) relate
to false alarms. To some extent these can be overcome by the use of good alarm
management processes.
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Efficient Measures (6 to 8)
 In addition the following two measures are slightly on the positive side based on the
parameters in our reference case but their potential is low and could be eroded by
false alarms:
- F7-Sliding Wheel Detectors.
- P16-Wheel Profile Detectors.
 Finally, measure F7 is to the best of our knowledge a market with only a small
number of suppliers. This may give rise to market advantage to existing suppliers of
these systems.
 We consider the following mitigation measure as potentially efficient if the significant
identified drawbacks could be solved:
- M1a-Derailment Detection (with automatic brake application) applied to All Freight Trains.
- (An alternative type of derailment detection device which provides an alarm to the train driver
when a derailment is suspected, but without an automatic brake application (type M1b) may
address this drawback. However we not aware of these being available on the market for
general freight application. An assessment of these devices, considering the human factors
issues involved and their costs, would be required before these could be formally assessed.)
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Efficient Measures (9 and 10)
 F-2: Awareness Programme for Rolling Stock Maintenance. This measure may
serve to address the problem of poor maintenance standards of rolling stock. This
may include training that sought to concentrate on main rolling stock maintenance
derailment causes (which can be extracted from this work). This measure may be
followed by increased supervision of these parameters by NSAs.
 P-18: Track Geometry (all tracks). The problem of poor track geometry (in particular
track twist) should be considered. This is of course an area for each IMs own
management system. However a specific measure in this regard must be
concerned with increased supervision of these parameters by NSAs to ensure that
documented standards are being met.
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End of Session - Any Questions
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Safeguarding life, property
and the environment
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