Melbourne–Brisbane Inland Rail Alignment Study - Australian Rail ...

4.5 Single track
A further important assumption about the inland railway is that it will be single track for most of its length.
For the coastal railway from Junee to Melbourne, ARTC plans to duplicate this track around 2013. 22
The box below provides information about single track railways.
BOX 6 Single track railway
Many railways in Australia and around the world are single track, where trains run in both
directions on the one line. The extra cost of double track (providing separate tracks for
each direction of travel) is only justified for busy lines with high volumes, particularly
those used for commuter services in cities or on busy freight lines like the Hunter Valley.
On a single track railway, trains running in opposite directions can pass one another only
where sections of track are provided for this purpose, termed passing loops or crossing
loops. (In railway terminology, trains passing one another are said to ‘cross’.) The same
applies to overtaking moves: for example a passenger train can only overtake a slower
freight train at a loop, where the freight train waits for the faster train to go past. The term
‘passing lanes’ is sometimes used for longer loops, for example those which have been
built on the remaining sections of single line between Melbourne and Sydney.
Train A
Train B
The process of crossing trains on a single track railway will always result in delays to at
least one of the trains involved, as the train that enters the crossing loop must stop to wait
for the opposing train to pass. The length of this ‘crossing delay’ will depend on the relative
timing of the two trains’ arrival at the crossing loop. The challenge is to reduce crossing
delays to a minimum, through the provision and optimum placement of adequate loops, and
though timetabling and control of train operations, and through trains being driven within
times allowed on each section. Modern signalling and control systems, such as ATMS
(planned to be introduced by ARTC and assumed for the inland railway), assist in managing
crossing movements. Nevertheless some level of delay due to crossings is inevitable, and
must be allowed for in the timetable. In principle, delay on single track lines is minimised by
a combination of adequate capacity, modern signalling and operational control, appropriate
driving and use of reliable rollingstock. Thus all stakeholders are involved.
As traffic grows on a single track railway, the number of crosses experienced by each train
increases and hence the total crossing delays increase – leading to a longer end-to-end
journey time for each train. The most cost-effective way to reduce these delays is to build
more crossing loops. If this is done, a train will not have to wait so long for an opposing
train to arrive and go past, allowing it to resume its journey sooner, thus reducing the delay
associated with each individual cross. Adding loops is usually a much more cost-effective
way of reducing overall transit time than shortening the line by building new track,
termed a deviation.
On the inland railway it has been assumed that sufficient crossing loops will be
provided in the initial construction to cater for the level of traffic expected at that time
and for some future traffic growth.
4.6 Track categories
The design, construction and maintenance of railways in Australia are documented in standards that generally cover
individual states or apply network-wide. Different principles are adopted in the various locations, although a national
code of practice is expected to be in place by the time the inland railway is in operation.
For the purposes of this report, the use of track categories (Class 1 and Class 2) has been adopted for the
specification of standards for the construction and maintenance of the proposed and existing alignments.
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ARTC 2008, 2008-2024 Interstate and Hunter Valley Rail Infrastructure Strategy, 30 June 2008, p33
4. Performance specification and design standards
ARTC • Melbourne–Brisbane Inland Rail Alignment Study – Final Report
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