The Melbourne Underground Rail Loop – usually called The City Loop, or just The Loop – is
an underground railway line encircling the Melbourne Central Business District.
The Loop opened in stages in the early 1980s, with a goal of distributing passengers more
evenly around the CBD, thereby relieving pressure on the extremely busy Flinders Street station.
While lots of cities around the world have circular rail systems around the inner city,
Melbourne's City Loop is quite an unusual design, and operates in a way that can be very confusing
for passengers. In this video I'm going to explain how the Loop is physically laid out,
why that creates unusual operating patterns, and how that compares to some other systems.
The Loop is at the centre of Melbourne's large suburban electrified railway system.
If you're not familiar with Melbourne, it's important to understand that the Loop is not
a dedicated subway or metro system – despite the current private operator being misleadingly named
Metro – it's part of Victoria's state-wide broad gauge heavy-rail railway network.
There are 5 stations located around the Melbourne CBD – Flinders Street and Southern Cross are both
large above-ground stations, linked by the elevated Flinders Street viaduct. Flinders
Street is the traditional hub of suburban trains, while Southern Cross is the terminal for regional
and interstate trains. Then there are three stations on the underground City Loop: Flagstaff,
Melbourne Central and Parliament. It's important to clarify that the name 'City Loop' generally
only refers to the underground lines running along the northern and eastern sides of the CBD, not
the above ground area to the south and west. All Melbourne's suburban lines radiate from the CBD,
and all have access to the City Loop – although not all lines use it on a regular basis. The Loop
is actually made up of four completely independent tunnels. Each is single track, and caters for
a group of lines – known as the Northern, Clifton Hill, Burnley and Caulfield groups.
Each underground station consists of two island platforms, one above the other. The
upper deck is used by the Clifton Hill group on platform 1 and the Caulfield group on platform 2,
with the lower deck catering for the Northern group on 3 and Burnley on 4.
The tunnels themselves do not form a complete loop shape – rather, each tunnel is essentially
shaped like a fish-hook, with one end of each tunnel pointing inward toward Flinders Street and
Southern Cross, while the other end points out to the suburbs. And yes there is one small exception
to that, which I will talk about shortly. Because each group shares a single track tunnel,
the group as a whole must travel around the Loop in the same direction at any given time.
However the tunnels are signalled for bi-directional operation, and traditionally,
the direction of travel changes half way through the day – although in recent years this practice
has been discontinued for two of the groups - more on that in a minute – This midday direction change
is what makes the operation of the Loop really unusual – I'm not aware of anything quite like it
elsewhere in the world. Most suburban services are timetabled to start or end at Flinders Street, and
the original idea was that in the morning, trains would run in via the Loop first, before arriving
at Flinders Street, where they would either terminate, or run directly back to the suburbs.
In the afternoon, trains would run directly in to Flinders Street or originate there, then
run out via the Loop on their way to the suburbs. Because the Northern Loop is the reverse shape of
the other three tunnels, it meant that at those times trains still ran through the Loop in both
directions. The big flaw in this plan was that at certain times, it was impossible to catch a single
train directly between certain major stations – for instance in the morning it was impossible
to travel directly from Flinders Street to any of the loop stations, and the opposite problem
existed in the evening. Although to be fair most of the time you could just walk or take a tram.
This has been partly solved in recent years with the Clifton Hill loop being made to run
permanently clockwise in 2013, and the Caulfield loop permanently counter-clockwise in 2021.
These changes were made for two very different reasons – The Clifton Hill loop had been plagued
by a terribly designed junction at Jolimont, where the tunnel entrance is located on the
northern side of the double track line. This meant that in order to run counter-clockwise,
Up trains had to cross the Down line from Flinders Street, creating a real bottleneck. It's kind of
mind-blowing that they went with this design, especially as every other Loop entrance is fully
grade separated. For instance if you look at this example at North Melbourne, the ramp drops down
between the Up and Down lines, meaning there is never a conflict. In fact the Northern loop tunnel
has two entrances at North Melbourne, allowing fully grade separated access from four platforms..
and a similar arrangement exists at the Richmond end of the Caulfield tunnel.
So after years of annoyance and with the system getting constantly busier, it was decided to fix
the Jolimont problem by sticking with clockwise operation at all times. The situation for the
Caulfield Loop was different. In 2020 the tunnel was modified to accommodate the new HCMT trains.
Being longer than existing trains, the HCMTs have to pull up right at the end of the platform, which
means the signals had to be moved slightly further into the tunnel to remain within the driver's line
of sight. These modifications were only done to signals in the counter-clockwise direction,
and now the Caulfield Loop always runs that way. It's worth noting that both those tunnels
do retain their signals for operation in the other direction, but it only happens for special
workings outside normal operating hours. The remaining two groups which still feature the
direction change now only do so on weekdays, with the Northern Group and the Burnley Group running
clockwise all day on weekends. Even with these changes, it is still only possible to travel
directly between the Loop stations and North Melbourne in one direction at any given time,
and a direct trip from the Loop out to Richmond is not possible on weekday mornings or weekends.
So why did they do the whole direction change thing in the first place? Well the answer
most people give for this is that running via the Loop first in the morning and last in the evening
helps to deliver commuters more directly to the busier parts of the CBD, or that it spreads people
out more evenly. While there are some elements of truth there, there's actually a more practical
reason why this style of operation was chosen – until the early 1990s, a large proportion
of Melbourne's suburban trains were stabled in Jolimont yard, and maintained at Jolimont
workshops, both of which are now long gone. In the 1980s the network was also much more peak-centric,
with off-peak patronage being comparatively very low. A lot of trains stabled at Jolimont yard
between the peaks, or were divided, with part of the train running to stable. So operationally,
it made sense to run in via the loop, terminate at Flinders Street then shunt out to stable
in the nearby yard, reversing the process in the evening. If it wasn't for Jolimont yard, I suspect
the loop may have been designed very differently, and might have been a bit more practical today.
So how else could you design something like this? At first glance, Sydney has a very similar
situation with their City Circle. However it has a much simpler design, and the operation
is much easier to understand. The City Circle was built in stages between the 1920s and 1950s,
which gives it a totally different character to Melbourne's City Loop.
The City Circle is shaped like a partly deflated balloon,
with the neck of the balloon pointing south towards Central station. The Circle is a
simple double track arrangement, with trains travelling in both directions at all times.
Very broadly speaking, trains coming from the west enter the western side of the Circle, run around
clockwise then form trains toward the south-west and vice-versa. Even for trains not following
that pattern, conflicts are largely avoided due to this awesome flyover just south of Central.
The balloon shape means every train passes through Central twice, and avoids Melbourne's
problems of uni-directional running and routes that are difficult at certain times of day. It
also means that if you're coming from the south or west and heading for Central – which is Sydney's
main terminal for regional and interstate trains – it's always the first stop as you enter the city.
Likewise if you're heading home, you can always find a train running directly out to the suburbs.
It's often quite frustrating in Melbourne having to board a train which departs 'the wrong way'
and takes you all the way around the Loop before your journey home really even begins – something
that can add anything up to 10 or 12 minutes to your journey time, depending on where you are.
Being a simple double track arrangement, the City Circle is also able to share capacity
evenly across all lines which use it, unlike in Melbourne, where some of the tunnels are used by
more lines than others. For instance the Northern loop is very busy, catering for the Upfield,
Craigieburn and Sunbury lines – and also Werribee in the past – whereas the Clifton Hill tunnel only
carries the Mernda and Hurstbridge lines. Overall, I think the design of City Circle
is way better and less confusing than the City Loop, however that's not to say a design like
this would have worked in Melbourne, as Sydney really benefited from the geographic position
of Central being.. not very centrally located, allowing for that balloon shape.
So back to Melbourne, and to clarify that thing I said about the tunnels not forming an actual
loop shape. There is actually a short connecting tunnel running from the Parliament end of the
Clifton Hill tunnel around to Flinders Street, known as the City Circle – not to be confused
with Sydney's City Circle, or Melbourne's other much more well known City Circle.
This allows trains to run in an actual indefinite circle around the city, and in the early days of
the Loop there was a service which did just that – which I guess was the solution at the time to
the no-direct route problem. It was discontinued in the early 90s when the much slower and lower
capacity City Circle tram began operation. The tunnel is still used today, but fairly
infrequently – as far as I can see there are no publicly timetabled trains that use it any more.
So the shared part of the Clifton Hill tunnel is actually called the Clifton Hill/City
Circle Loop. In this footage here, we're travelling around the curve in the Northern
Loop tunnel approaching Flinders Street, and you will notice that the tunnel changes shape.. HERE.
This is because the tunnels were mostly dug using a circular tunnel boring machine,
but the shallow bits near the entrances were built using cut-and-cover. So that's why the tunnels are
rectangular when viewed from above ground, but circular when viewed from the stations.
The way the City Loop is operated can be very confusing to passengers, and the various public
transport agencies have never done a particularly good job of presenting the information clearly.
For instance, trains heading into the city running around the Loop and then to Flinders Street are
described as 'via the City Loop.' However to the untrained eye, there's no way of knowing that
'City Loop' refers specifically to the underground bit, and if you just look at the map, you'd
probably assume the 'Loop' is.. you know.. that whole loop shaped bit in the middle of the city,
so it doesn't clearly explain what route the train is taking. With the vast majority of services
technically beginning or ending at Flinders Street, there is also no onboard information
about where the train will continue AFTER Flinders Street, despite the fact that most direct trains
will immediately form another service that runs around the Loop. This has created a funny sort
of ritual, where as a direct train arrives at Flinders Street, people peer out the windows
or even open the doors to check whether or not the train is continuing in the right direction.
“Yeah, you can stay on.” “Stay on?” “Yep.” “It's goin' to Southern Cross?”
“Yeah” “Thanks very much.” “No worries.”
It's not uncommon for trains to be transposed onto a different group of lines at Flinders Street,
which may not be using the Loop in the same direction. There has been some effort to clarify
these things in recent times, with platform displays like THIS showing the next trains to
take towards the other major stations. However, I reckon that still just looks fairly confusing,
and it also completely ignores the existence of Jolimont station. The midday direction change
also creates this confusing timetable layout, where the city stations are listed twice,
allowing both clockwise and counter-clockwise running to be shown on the same page.
Something else that makes the Loop a bit unusual, is that when it first opened back in the 80s,
it didn't operate on Sundays. This really shows how low weekend patronage was at the time.
Even after it began operating daily, Flagstaff station remained closed on weekends, and this
remarkably continued up until the start of 2016. The reason this lasted so long was basically
because Flagstaff is in the most boring corner of the CBD and mostly serves the law courts,
which only operate during the week. However Flagstaff is actually the best place to
interchange with tram route 58, and is also close to the Flagstaff gardens, the Vic Market and a
bunch of other things.. so finally being able to use it every day of the week was a big win.
There is one last vestige of this practice – suburban trains run all night on Friday and
Saturday nights, but the late night trains – roughly between 1 and 5am - don't use the
City Loop, departing only from Flinders Street. Forgetfully rocking up at Melbourne Central at
2 in the morning to find it closed then having to drunkenly run down Swanston Street to catch
your train, is a Melbourne tradition we probably could have done without.
Despite all its oddities, the City Loop has remained a crucial part of the suburban system
into the 21st century, and the stations have aged quite well, remaining reasonably
functional and attractive designs. Pressure on the Loop is set to be eased slightly in
next couple of years when the Melbourne Metro Tunnel opens, which will carry the Pakenham,
Cranbourne and Sunbury lines, freeing up capacity in the Caulfield and Northern loops. If you'd
like to see more footage of operations in the City Loop, I've made quite a videos down there,
and also some on Sydney's City Circle, which you can check out in this playlist.
I hope you've enjoyed the video, and hopefully you've all learned
something about the operation of Melbourne's wonderful but confusing underground railway!