PR S 40007 Flashcards
Seldom used
what is seldom used
equipment that is not used within defined periods
give some examples of equipment that can become seldom used
track circuits, points, ETCs, signals, trainstops, level crossing equipment
what are the types of situations/events that can attribute to equipment becoming seldom used
operational changes, environment and weather, seldom operated or traversed equipment, rolling stock characteristics, engineering activities, track configuration changes
what are some examples of causes of seldom used
changed timetable, flooding, sidings and refuges, light engines only, unplanned trackwork, changes of track configuration.
why is a track circuit that becomes seldom used dangerous
it can become contaminated which affects the ability of a train to shunt the track circuit effectively, leading to loss of rail vehicle detection.
How do you protect trains from seldom used equipment
you book out and disconnect the equipment and its protecting signal and any associated or affect equipment.
What are some controls for mitigating equipment becoming seldom used
Proactive maintenance plans, controls implemented by the signal engineer responsible for the work, rail vehicles are managed by the TOC
What is the minimum tonnage or amount of trains required over track circuited lines
5000 tonnes or 6 8 car sets over 24 hours.
What must be done to help identify track circuits from becoming seldom used
scheduled maintenance and visually inspecting the rail for any contamination or debris build up.
how do you test a track circuit if you are unsure it is seldom used
do a train shunt check and compare to PR S 400025 values. if no acceptable they must be booked out and signal engineer notified.
what equipment or functions of the interlocking can be affected by seldom used
Approach locking, ARS automatic route set, level crossings, speed checking.
who is reponsible for management of the register of seldom used apparatus
the maintenance signal engineer
what can be altered to maintain good rail surface condition
a change to the tabled trains through track circuits and associated points
what is the 72 hour rule
It is a specified period of time of unuse of track circuits that immediately qualifies it as seldom used.
what is the cleaning action by trains running on rail called
Scrubbing effect.
Where does the 72 hour rule not apply.
axle counter sections
Can the 72 hour rule be varied
Yes it can be shortened or extended due to considerations.
factors to consider for determining safe use of signalling system
effectiveness of track circuit shunting, location of contamination, environment, rolling stock, affected signalling equipment, maintenance and admin controls in place.
give some examples of causes of seldom used track circuits over large areas
flooding, fires, operational changes, landslides and washaways, trackwork, incidents, possessions.
what are the 3 examples of trackwork/closed lines causing seldom used
Track circuits directly worked on, track circuits within the possession area not sufficiently traversed, track circuits outside the possession area not sufficiently traversed.
Can a line be certified if flooded even for only 10 minutes
No. It is irrespective of the time limit as there can be slurry, mud or sand deposited on the rail head.
What are the 3 ways to test a large area
Train shunt.
Train occupancy test with test locomotive.
train occupancy test on panel with tabled or specially run trains.
how long between the train shunt/occupancy check does certification need to be completed
within 24 hours.
can trains be run through seldom used tracks before certification
yes but they must be blocked work through in accordance with NSY 512
