INSTITUTION OF RAILWAY SIGNAL ENGINEERS
2014 EXAMINATION
MODULE 7 - SYSTEM MANAGEMENT AND ENGINEERING
TIME ALLOWED - 1 1/2 HOURS
ANSWER THREE QUESTIONS, ALL QUESTIONS CARRY EQUAL MARKS
WRITE ON ONE SIDE OF THE PAPER ONLY, AND NUMBER EACH SHEET THAT
YOU USE CONSECUTIVELY
COMMENCE YOUR ANSWER TO EACH QUESTION ON A NEW SHEET OF PAPER
ANSWER SHEETS WILL BE PHOTOCOPIED – PLEASE USE ONLY BLACK INK
Question 1
A hazard arises when a track circuit shows clear when actually occupied. Show by means of an
event tree all of the possible intermediate conditions and accident consequences (no collision,
minor collision and major collision) for this scenario on a section of plain line with automatic
signals.
[15 marks]
Propose realistic probabilities for each of the intermediate conditions identified in your event
tree, and use these to determine the overall probability of each of the accident consequences.
[10 marks]
Throughout your answer to this question, you should state any assumptions that you make and
ensure that you take account of any other train movements which could be taking place at the
time.
Question 2
What Human Factors should be considered when designing the configuration of a control desk
that will be used as part of a centralised control centre for a busy railway?
[15 marks]
How might degraded and emergency operations impact on the needs of the intended user of the
control desk?
[5 marks]
In what ways could the design of the wider control system support or hinder operators in
degraded conditions?
[5 marks]
Paper continued on next page
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Question 3
Compare and contrast the whole life-cycle environmental impact of building a new low speed
metro type railway to transport passengers to/from an airport and to connect them to existing
rail links in a nearby city, versus investment in additional infrastructure for road travel to/from
the airport and on to surrounding regions.
[10 marks]
Assuming that the new metro railway is to be built, identify the four aspects of the railway’s
design and operation that you believe would most significantly influence the level of
environmental impact. For each of these identify:
i)
ii)
The approach that should be adopted in order to achieve minimum environmental
impact.
[5 marks]
Other factors that should be considered alongside environmental issues when
determining the most appropriate approach to design and operation. Highlight the
significance of each of these factors within your answer.
[10 marks]
Question 4
Discuss the causes of varying wheel / rail interface conditions on an open air suburban railway.
[10 marks]
For the causes that you have identified, provide realistic examples of the impact that they might
have on the railway’s performance
[5 marks]
An existing manually driven, open air, suburban railway is introducing Automatic Train
Operation. What new requirements need to be imposed on the new system (whether for the
signalling system, ATO elements or supporting systems) in order to support both safe and
reliable operation within the full range of possible wheel / rail interface conditions that you
have identified?
[10 marks]
Question 5
A new high speed line electrified at 25kV ac will run parallel to an existing commuter line
electrified at 750V dc with a minimum of separation between the two sets of tracks. The two
lines are operated by different companies and are controlled from different locations.
What technical measures and operational arrangements should be adopted by each company in
order to ensure the safety of train movements and the safety of maintenance activities?
You should take account of normal operations, degraded modes of operation and emergency
situations.
[25 marks]
Paper continued on next page
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Question 6
What factors should be taken into account in the management of staff who work on
maintenance of safety critical systems? Your answer should address issues associated with
diverse equipment types and locations, including line-side locations.
[25 marks]
Question 7
What aspects of railway system design and operation need to be harmonised in order to ensure
safe, reliable and economic operation of international train services without the need to change
crew or motive power units at national borders? You should consider both passenger and
freight services.
[25 marks]
Question 8
How are reliability, availability and maintainability related to one another?
[5 marks]
If an electronic system has a mean time between failures of 15,000 hours and a mean time to
repair of 1.5 hours, what is its availability?
[5 marks]
What factors determine the time needed to repair a system?
What design features can be incorporated in an electronic system to improve its
maintainability?
[5 marks]
[10 marks]
Question 9
Explain what is meant by the term Communications Based Train Control (CBTC).
[5 marks]
Draw a diagram showing the main elements of a CBTC system. Indicate which elements need
to be developed to a high level of safety integrity and which elements could have a lower level
of safety integrity.
[10 marks]
Suggest three types of communication media which would be could be used to transmit data
between fixed equipment and trains, including at least two which would be suitable for use
underground.
[5 marks]
How is train position usually determined in a CBTC system?
Paper continued on next page
Page 3 of 4
[5 marks]
Question 10
What items of information should be recorded in a FRACAS or DRACAS system covering the
signalling and/or telecommunications equipment of a railway network in order to support the
growth of reliability?
[10 marks]
Explain how each item of information might contribute to the development of measures which
would improve reliability in future?
[10 marks]
Suggest a number of factors which might cause an item of equipment to fail more frequently in
one location than in others.
[5 marks]
End of paper.
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