When faced with a overcrowded peak hour train, “why don’t they add another carriage” sounds like a obvious fix – but unfortunately the answer isn’t always that simple.
To start with, the ‘extra carriages’ have to exist. In the case of the Melbourne suburban fleet, trains are formed into fixed 3-carriage sets.
With a drivers cab at either end and electrical equipment scattered between the different cars, these 3 car long trains can’t be broken up into single carriages and then added to other trains to make them longer, at least without lots of modification to make it all work. The same applies to many other rail networks – you can’t just mix and match carriages to make a train.
Once you get the extra carriage sorted, you need a platform long enough for passengers to board.
It doesn’t make sense to build platforms longer than the longest train, so once you start adding carriages, you also need to start extending platforms – a difficult enough activity in busy urban areas, which becomes incredibly expensive if you are dealing with underground stations.
Now that the passengers can board the train, your troubles aren’t over – you need to get those trains running.
Signalling systems are used to keep trains a safe distance apart. They do this by dividing the tracks into a series of blocks, where only a single train is permitted, and a ‘clear’ zone behind each train to provide a safety margin.
Diagram by the UK Parliamentary Office of Science and Technology
Once you start making trains longer, they can start to overlap the signalling blocks, which doesn’t affect safety, but does reduce the capacity of the railway, thanks to longer than required gaps being left between trains. The only solution – twiddle with the existing signalling system to allow for longer trains, or upgrade to a moving block signalling system to run even more trains on the same tracks.
You also need to supply more electricity to power these bigger trains.
So upgrades to the traction power system might also be needed.
Now that the trains are moving, those extra passengers need to go somewhere once they arrive at their destination. Are there enough escalators linking platforms to the station concourse?
Are there enough ticket gates to let these extra passengers exit the station?
And are there wide enough footpaths around railway stations so they can get to their workplace?
I said it was difficult, didn’t I?
And two bonus issues
The problems don’t end when the passengers leave the train – trains have to be parked somewhere between runs, usually in sidings designed to accept trains of a given length.
The same considerations apply to maintenance facilities and workshops.
Once you start extending trains you either need to break up trains into smaller sections to make them fit existing sidings, or extend the sidings as well.
One dirty hack
One way to make longer trains work on constrained rail networks is selective door operation – leave the infrastructure as is, and only allow passengers to use part of the train at short platforms. This only avoids the need to lengthen platforms, but doesn’t address any of the other issues I’ve listed above, and can result in a net loss of capacity, as platform dwell time blows out due to passengers passengers crowding the doors that are in use.
Coming soon: how is Melbourne getting around these problems?
Melbourne currently has new 7 car long ‘High Capacity Metro Trains’ on order – one carriage longer than our existing trains. How will they fit onto our existing network – a future post will cover this.
Melbourne has extended trains (and platforms) twice already.
When Melbourne’s suburban network was electrified just after WWI, the maximum length train was six cars (MTMTTM). The electrification was so popular and patronage grew so much that commencing around the mid ’20s the VR purchased new trailer cars and moved (slowly) to seven car trains (MTTMTTM). This required platform extensions, and lines were slowly converted over about eight years.
In the late ’60s, patronage growth on the outer suburban lines was again causing congestion, and the VR undertook a program of extending the seven car Harris trains to eight cars. Again, this required a program of platform extensions – and these can still be seen at many locations where the platforms are now much longer than required (Windsor is a good example). The first eight car trains were introduced in 1967, and conversion was line by line. The Camberwell group was first, and then, from memory, the Frankston line.
Thanks for the extra history Andrew – I’ve been slowly trawling thorough ‘The Electric Railways of Victoria’ by S.E. Dornan and R.G. Henderson, with a post on this topic coming at some point in the future.
What about double decker trains? Are they suitable in Melbourne or not?
Back in the 1990s a single ‘Double Deck Development and Demonstration’ (4D) train was built and ran on the Lilydale and Belgrave lines, via the City Loop.
https://en.wikipedia.org/wiki/4D_Train
So there is no reason why they couldn’t be used in Melbourne, but there is a continual debate whether the extra capacity is worth it given longer dwell times at stations:
http://www.abc.net.au/news/factcheck/2014-04-11/barry-ofarrell-sydney-trains-claim-doubtful/5371446
The photo of the electrical substation is along the Upfield Line just north of Camp Rd, right? I wonder what will happen to it with the level crossing removal works happening. Or would it only be affected by duplication? Or a new Campbellfield station? I believe power is being upgraded down around Brunswick.
Spot on for guessing the substation location.
Level crossing removal works at Gardiner, Bentleigh, Ginifer and Blackburn left their substation as-is, with just the traction feeder cables relocated, so Campbellfield might get left alone as well.
That is good news Marcus! If it remains there, then there would obviously be enough room for a desperately-needed bike path. At least until duplication occurs.
what about v/line services, aren’t they able to run 7-9 car trains as many platform extensions have occurred over the past few years
Seven car platforms were rolled out to some Geelong lime stations in 2008:
https://wongm.com/2017/08/vline-7-car-vlocity-trains-geelong-line/
But I believe all other extensions have all been to allow a six car VLocity to stop at the platform without hanging off the end.
The previous extensions to suburban platforms, to 7 and then 8-car trains, were for shorter carriages. After the lengthenings commenced in 1967, new train designs had longer carriages (except for the double-decker train, which had the old length because the end only door model of the double-decker trains needs shorter carriages).
Spot on – Melbourne’s early suburban trains were all ‘short’ carriages:
– Swing Door: 17.4 metres (57 ft 1 in)
– Tait: 18.8 metres (61 ft 8 in)
– Harris: 19.20 metres (63 feet)
The first ‘long’ carriages were the prototype Harris trailers at 22.86 meters (75 feet).
The Hitachi and Comeng trains that followed were the same ‘long’ size, plus or minus a metre.
[…] few months ago I went into detail why ‘make trains longer’ isn’t that simple – go have a read now if you […]
There doesn’t seem to be any problem with making platforms longer than all trains. It could make sense, it keeps a future option open.
That is reasonable for new platforms, however most of the platforms on the system are decades old and need extension work for trains to be extended (or in the case of Essendon platform 1 an extension to cope with existing trains) and that is near impossible for the City Loop (7-car trains can be fitted at a stretch but anything longer would require replacing existing tunnel with platform at enormous cost).
[…] out running more trains isn’t the silver bullet to increasing the number of passengers able to travel – capacity on the escalators and through ticket gates at railway stations is […]