Can loop service trains be separated by less than 2 minutes?

 
  Ummagumma Junior Train Controller

Location: Junction, Rosstown and Oakleigh lines
In the so-called Transport and Liveability Statement released by the Government in May, "Meeting Our Transport Challenges", http://www.doi.vic.gov.au/DOI/Internet/planningprojects.nsf/AllDocs/D3D0D6B6C599955ACA257169001A4DF9?OpenDocument, an upgrade of the Loop signalling system was announced as going ahead in 2008.

What could a state-of-the-art signalling system do as far as reducing the distance between loop trains?

I notice the new Connex timetable has the 5.33pm Dandenong service running just two minutes behind the 5.31 Frankston service (keeping the same two-minute spacing in the loop), whereas I've always noticed that trains leaving Flinders St in the evening peak have previously always taken off at three-minute intervals.

So how closely could they run? This question crossed my mind the other day after seeing a tram running just metres behind another one through the Bourke St Mall. Why do trains have a forced buffer when trams don't?

Any thoughts?

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  jarf Chief Commissioner

Location: Bunzelling!
I believe there is a limit of 24 trains per hour, so every 2.5 minutes.

I'm open to correction though. Wink
  The Vinelander Minister for Railways

Location: Ballan, Victoria on the Ballarat RFR Line
IMO dwell times are the real problem.

For example, (purely hypothetical)if no trains were to stop in the loop, you could probably get trains through at the rate of one every 30 seconds or less, however the dwell times are what slows everything up.

Mike
  psr85 Chief Commissioner

Location: Sandringham Line, Melbourne
So how closely could they run? This question crossed my mind the other day after seeing a tram running just metres behind another one through the Bourke St Mall. Why do trains have a forced buffer when trams don't?

Any thoughts?
"Ummagumma"
Trams are like busses trains are longer and have more momentum in them, think about how easy it would be to stop a bus versus a very long road train.

A train can't run too close behind another train because of the time it takes to stop. A tram can round a corner see another tram and stop in time, a train would run up the back of it.

IMO dwell times are the real problem.

For example, (purely hypothetical)if no trains were to stop in the loop, you could probably get trains through at the rate of one every 30 seconds or less, however the dwell times are what slows everything up.

Mike
"Mikelander"
Always the damned passengers creating a problem. Imagine how fast our trains could go from Flinders Street to each terminus if they didn't have to stop!  Razz

The only thing that could help improve dwell times are smarter passengers, and possibly more doors with longitudinal seating to create more standing room.

The best solution is to not make every train run through the loop. That could help clear the backlog and the possibility of more services, of course you run into problems later down the track where other bottlenecks exist, such as platform shortage at termini and single track sections.
  Gwiwer Rt Hon Gentleman and Ghost of Oliver Bulleid

Location: Loitering in darkest Somewhere
You could probably get trains through at slightly closer intervals provided they all ran at the same speed and didn't need to stop at all.

As soon as you introduce station stops you increase the headway required through braking, accelleration and dwell time.
  mjja Sir Nigel Gresley

Location: Mount Waverley, Melbourne

Idea If they all ran at EXACTLY the same speed we could just couple them up and run sixty trains a minute! Save on drivers, too! Laughing
  lordofthesheep Train Controller

Location: Where facts are few and experts are many, Vic
The elevated section between Flinders St and Southern Cross can't be very good for the loop either, all the trains I have ever been on along there have gone woefully slow, probably due to a speed limit. If this section were improved then there might be a more efficient service
  tranzitjim Chief Commissioner

Location: Banned
There would need to be time for points to change at the tunnel ends, like in the Caulfield and North Melbourne loops.

They may take only a few seconds to move over, but there needs to be something of which says that the last train has gone past, turn the signals red, to ensure it is safe to change over, then to chage over, and then the signal is turned green.  This all takes time.

Does anyone know how long this would take?

Perhaps they could speed things up by having trains exit the loop via the same porthole (Caulfield/North Melbourne loops) and have the first one run express, and the following stop all stations.  this would give them headway at say Caulfield.     This goes on, but this will do from me.
  madmac01 Chief Commissioner

The elevated section between Flinders St and Southern Cross can't be very good for the loop either, all the trains I have ever been on along there have gone woefully slow, probably due to a speed limit. If this section were improved then there might be a more efficient service
"lordofthesheep"



Yeah its 40 km/h or 35 km/h depending on which loop line you are on.

Biggest problem is to many trains and not enough infrastructure to support them.

Enough said!
  MelbourneCity Chief Commissioner

Idea If they all ran at EXACTLY the same speed we could just couple them up and run sixty trains a minute! Save on drivers, too! Laughing
"mjja"


Why not a high capacity travellator?
  lordofthesheep Train Controller

Location: Where facts are few and experts are many, Vic
Idea If they all ran at EXACTLY the same speed we could just couple them up and run sixty trains a minute! Save on drivers, too! Laughing
"mjja"


Why not a high capacity travellator?
"MelbourneCity"


Or a gas tube with capsules, like in James Bond.
  EvanC Chief Plonker

Location: Bayswater, Victoria
Idea If they all ran at EXACTLY the same speed we could just couple them up and run sixty trains a minute! Save on drivers, too! Laughing
"mjja"


Why not a high capacity travellator?
"MelbourneCity"


Or a gas tube with capsules, like in James Bond.
"lordofthesheep"
Or just the tube, like in Futurama! Very Happy
  SPSD40T2 Chief Commissioner

Location: Platform 9-3/4 and still waiting !!
aboutthe only way to drop  times between trains in teh loop  would be to completely automate it..( and yes i know the limitations of such thiking ) ...but if a computer system was developed to take over from the drivers..and completely control the trains through the process of travelling in that region then it could further marginalise the times between trains..
all quite feasible .. highly unlikely
  The Met Chief Commissioner

Location: 37.55-S /145.01-E

aboutthe only way to drop times between trains in teh loop would be to completely automate it..( and yes i know the limitations of such thiking ) ...but if a computer system was developed to take over from the drivers..and completely control the trains through the process of travelling in that region then it could further marginalise the times between trains..
all quite feasible .. highly unlikely



Um...

The New York Metro runs at less than 30 seconds between each train on peak occasions.

Leeway of under a minute is definately possible in Melbourne - though you would need to have a little more signalling (hence the perfect speed & timing) in order to run such type of operations...

We have to thin down the gaps, and improve the entire system overall...

Coz if we can fix it in the Loop - just imagine the possibilities outside of the Loop... Make Delays History!
  SPSD40T2 Chief Commissioner

Location: Platform 9-3/4 and still waiting !!
even easier

its all in the loop..  that is the chicane in the system
  Hitachi_178M Hitachi's Are Us

Location: Portland/Heywood/Hamilton
i hurd along time ago that there is a train system that dosn't have drivers thay just have workers on every station that make people get on and off fast and the operations run alot better there and with workers at every station theres not late trains
  comeng_2006 Junior Train Controller

Location: Frankstoned Line
Personally, I dont like the idea of computers controlling the trains instead of drivers, computers always stuff up at some stage. I'm glad it won't be happening here anytime soon.
  station street Chief Commissioner

Agreed, with the above post!

I think that the loop's signalling should be re-configured to the smallest headway possible, but still feasable for Melbourne. I would like to see 30-seconds the bare minimum - and have some trains operating at 1 minute intervals. The problem with this is that I think you would probably end up with the loop taking something like 15 or 16 minutes  opposed to the current 10 at best conditions... (Ok - thats a bit of a best vs worst comaprison. Peak Loop services are generally 12 minutes)

  -   Station   Street
  Rocket Deputy Commissioner

There would need to be time for points to change at the tunnel ends, like in the Caulfield and North Melbourne loops.

They may take only a few seconds to move over, but there needs to be something of which says that the last train has gone past, turn the signals red, to ensure it is safe to change over, then to chage over, and then the signal is turned green.  This all takes time.

Does anyone know how long this would take?

Perhaps they could speed things up by having trains exit the loop via the same porthole (Caulfield/North Melbourne loops) and have the first one run express, and the following stop all stations.  this would give them headway at say Caulfield.     This goes on, but this will do from me.
"tranzitjim"


Track circuits return signals to stop immediatley the first set of wheels pass the signal circuit.
There are clearance points that determine that a train has moved off a section of track and allow the points to be altered.
Air operated points take about .3 of a second to throw. Circuit proving should then happen at the speed of light but with modern technology does not. It should all happen in the space of a few seconds once the previous train is clear.
The old Melbourne Yard area controlled by the West Tower is undoubtedly the fastest I have ever seen things happen. It is very fast if the signaller is 'on the job'.
By comparison the modern signalling technology that has been put in at Clifton Hill, Heidelberg and Ringwood is apallingly slow.
Over to an expert to explain the difference between the signalling at West Tower and Westrace signalling.
  Gwiwer Rt Hon Gentleman and Ghost of Oliver Bulleid

Location: Loitering in darkest Somewhere
The New York Metro runs at less than 30 seconds between each train on peak occasions
and the same is true on many inner sections of the London underground network.

Those lines are signalled and fitted with safety devices to match, which could be the case in Melbourne if the inner area were totally resignalled.

And those lines shift massive passenger volumes with, for example, London's Central Line running 8-car trains scheduled about 90 seconds apart (but capable of running at intervals as close as station dwell times permit, say 30 seconds); there is no doubt that very frequent trains helps to minimise dwell times as passenger numbers do not build up on the platforms.

London and New York do not (with a few exceptions) terminate trains in a central area through station, nor run them around a short loop where in some cases inbound trains must cross outbound ones on the level.

If Melbourne were to return to through trains across the city such as Sandringham - Williamstown or Upfield - Alamein more could probably be accommodated although the stand time at Flinders Street is also a constraint and would still need to be at least 2 minutes.  This would also mean potentially fewer passengers having direct loop trains than at present.
  BSW Locomotive Fireman

Hello all,
to automate the loop as in U.S., one would assume the need for barriers that would effectively stop pax entering the platform when a train is to depart. Also a means of stopping pax holding doors open or forcing doors open to catch the train as they run late.
Much of the trouble in maintaining the time table is due to the customer interference factor. Rolling Eyes
There is speed signalling in force in the loop, with additional train stops to prevent a train approaching signals at stop too quickly, therefore making the loop a safer system upon which to travel. The system forces drivers to average 30kph or less through the loop during peak times.

Goodluck and happiness in whatever you do

bsw@dodo.com.au
  kuldalai Chief Commissioner

As originally signalled the loops are signalled theoretically for 24 trains per hour which is one every 2.5 minutes. IIRC the only loop that is single tracked throughout (no points) is the Burnley Loop.

The others all have Y junctions and dual exit ramps at at least one end - Caulfield loop at Richmond end, Clifton Hill loop (as City Circle under Flinders St currently not regularly used, but will be used regularly again when one way running instituted on Clifton Hill loop in a clockwise direction), and Nth Melbourne Loop at Nth Melbourne station.

The capacity of 24 trains per hour is reduced to something like 16 per hour once the traffic is spread over the two exit points.  Government has announced loop will be resignalled to allow more trains to be put through, but also in future it would seem sensible to run some trains direct to Flinders St in peak hours when loops are at their new higher signalled capacity.
  The Met Chief Commissioner

Location: 37.55-S /145.01-E

Personally, I dont like the idea of computers controlling the trains instead of drivers, computers always stuff up at some stage. I'm glad it won't be happening here anytime soon



Please be aware - that many computer systems have a near 99.99% error free operation. With computer - it's even possible to say that there lesser chance of something going wrong, than with humans in control. Such example if you had computer controlling, you could adjust train speed, to arrive at the right time, and to maintain precise space between trains...






to automate the loop as in U.S., one would assume the need for barriers that would effectively stop pax entering the platform when a train is to depart.


Well they don't.


Also a means of stopping pax holding doors open or forcing doors open to catch the train as they run late.


Well they don't either...



The New York Metro runs at less than 30 seconds between each train on peak occasions  
"The Met"


and the same is true on many inner sections of the London underground network.

Those lines are signalled and fitted with safety devices to match, which could be the case in Melbourne if the inner area were totally resignalled.

And those lines shift massive passenger volumes with, for example, London's Central Line running 8-car trains scheduled about 90 seconds apart (but capable of running at intervals as close as station dwell times permit, say 30 seconds); there is no doubt that very frequent trains helps to minimise dwell times as passenger numbers do not build up on the platforms.
"Gwiwer"



The systems above - do not have any passenger interfering infrastructure (except ticketing and the doors).

Note that in the US - the slam doors have built a reputation for 'not caring' or in other words, if your in them - you get hurt - it's your fault... I personally think we're too friendly with our doors...

Nor do their systems have any barrier (like Hong Kong or Singapore) between station to train.

Biut there perhaps are indicators which show where to board - something we lack.

Aswell - is that our fleet, numer of doors per carriage - is significantly different configuration to theirs... (they have more doors, more standing room - we had a trade off with more seats - because theire systems focuse on Mass Movement, we have more of a suburban niche)


Much of the trouble in maintaining the time table is due to the customer interference factor.  


Perhaps - though it is true...


There is speed signalling in force in the loop, with additional train stops to prevent a train approaching signals at stop too quickly, therefore making the loop a safer system upon which to travel. The system forces drivers to average 30kph or less through the loop during peak times.


I don't think the 30kph would work too well, when we can run at near full speed. But as i said, drivers have more margin for error than computers...
  Gwiwer Rt Hon Gentleman and Ghost of Oliver Bulleid

Location: Loitering in darkest Somewhere

The systems above - do not have any passenger interfering infrastructure (except ticketing and the doors).

And Melbourne has what, exactly, over and above those?


Nor do their systems have any barrier (like Hong Kong or Singapore) between station to train.

I'm not quote sure what you mean, but London at least uses a ticketing and entry system almost identical to Melbourne with entry barriers; some tube stations also have sliding doors at the platform edge and a barrier between the train and the platform making it impossible to press up close to the train and to only enter and leave by the doorways.

The issue with Melbourne's loop capacity is largely the signalling system, and to a lesser degree the finite capacity of Flinders Street being used as a terminus with trains standing typically for 5 or more minutes at each platform.

High passenger volume is common to many urban systems; some cities expereince better manners than Melbourne where holding doors open is becoming endemic.
  MelbourneCity Chief Commissioner

Personally, I dont like the idea of computers controlling the trains instead of drivers, computers always stuff up at some stage. I'm glad it won't be happening here anytime soon.
"comeng_2006"


Driverless trains work fine in many cities worldwide.
- Singapore (NEL, Elevated LR)
- Vancouver (Skytrain)
- Toronto (Scarborough SRT)
- London (Docklands LR)
- Paris
- Copenhagen
- Bangkok (Skytrain)
- Kuala Lumpur

I dont think driverless trains would be suited to any existing Australian suburban network as the lines are not segregated 100%.

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