Observations and Questions from a trip to Sydney

 
  jdennis Junior Train Controller

Hi all,

I was in Sydney last week, and being from the country I have a few questions about the Sydney network that I thought someone on here might be able to answer.

Firstly, I caught a number of North Shore Line trains (as I was staying in a friend's unit in Wollstonecraft), mostly K sets with the occasional S set or Tangara. On the S and K sets I noticed a noise coming from underneath the driver's cabin, sort of like the sound a fridge makes when it is cooling itself down, only louder. It was intermittent and would start up occasionally before turning off again. Does anyone have any idea what this might be? I know the description is a bit vague but it is the best I can describe it.

During the week I often travelled into the city and got off at Town Hall. I know that Platform 3 is one of the most busy in the network during the morning peak, with a lot of people getting on trains, but why is this? It makes sense that a lot would get off as trains have come from the Western Line, but why would so many people get on a train leaving the city in the morning?

Thanks for any answers you can give me - they might be silly questions but I hope someone can help me.

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  bowralcommuter Chief Commissioner

Location: Asleep on a Manly Ferry
Hi all,

I was in Sydney last week, and being from the country I have a few questions about the Sydney network that I thought someone on here might be able to answer.

Firstly, I caught a number of North Shore Line trains (as I was staying in a friend's unit in Wollstonecraft), mostly K sets with the occasional S set or Tangara. On the S and K sets I noticed a noise coming from underneath the driver's cabin, sort of like the sound a fridge makes when it is cooling itself down, only louder. It was intermittent and would start up occasionally before turning off again. Does anyone have any idea what this might be? I know the description is a bit vague but it is the best I can describe it.

During the week I often travelled into the city and got off at Town Hall. I know that Platform 3 is one of the most busy in the network during the morning peak, with a lot of people getting on trains, but why is this? It makes sense that a lot would get off as trains have come from the Western Line, but why would so many people get on a train leaving the city in the morning?

Thanks for any answers you can give me - they might be silly questions but I hope someone can help me.
"jdennis"


A driver can answer your first question but the reason a lot of people are on the North Shore train is because a lot of people like me go to North Sydney, St Leonards and Chatswood for uni or work.
  jdennis Junior Train Controller

A driver can answer your first question but the reason a lot of people are on the North Shore train is because a lot of people like me go to North Sydney, St Leonards and Chatswood for uni or work.
"bowralcommuter"


That makes sense, but I didn't realise so many got on at Town Hall - is that where a lot of commuters from the Bankstown, East Hills etc lines that go around the City Circle change for a North Shore train?
  bowralcommuter Chief Commissioner

Location: Asleep on a Manly Ferry
That makes sense, but I didn't realise so many got on at Town Hall - is that where a lot of commuters from the Bankstown, East Hills etc lines that go around the City Circle change for a North Shore train?
"jdennis"


I change at Wynyard but a lot probably change at Town Hall too.
  Empdizz Junior Train Controller

Location: Somewhere on Sector 3
On the S and K sets I noticed a noise coming from underneath the driver's cabin, sort of like the sound a fridge makes when it is cooling itself down, only louder. It was intermittent and would start up occasionally before turning off again. Does anyone have any idea what this might be? I know the description is a bit vague but it is the best I can describe it.
jdennis
That would be an air compressor.
  darcyj Chief Train Controller

That makes sense, but I didn't realise so many got on at Town Hall - is that where a lot of commuters from the Bankstown, East Hills etc lines that go around the City Circle change for a North Shore train?
jdennis
Those that enter the City Circle from the Museum end are more likely to change at Wynyard (or even at Central, before entering the circle, saving at least 10 minutes).  However Town Hall is the most convenient changing point for Illawarra Line commuters who wish to proceed to Wynyard, North Sydney, Chatwood or Macquarie Park, as their pathway is simply up a flight of stairs from P5 to P3.  There are also likely to be a fair few who came into the city by bus and disembarked near Town Hall to join their train to proceed over the bridge.
  jdennis Junior Train Controller

That would be an air compressor.
"Empdizz"


So it's compressing air to be used for the brakes? Thanks for the answer, that makes sense.
  XAM2175 Assistant Commissioner

Location: Glasgow
So it's compressing air to be used for the brakes? Thanks for the answer, that makes sense.
jdennis
The long of it can be read here: https://en.wikipedia.org/wiki/Railway_air_brake

The short of it is that air pressure is used to keep the brakes off; so when that air pressure is decreased - either deliberately by the driver or accidentally through a failure - the brakes will come on. One or multiple compressor/s onboard the train is used to keep the air pressure at the correct level, so when the brakes are applied the compressor is topping up the air reservoir ready for the driver to release the brakes.
  simonl Chief Commissioner

Location: Brisbane
So it's compressing air to be used for the brakes? Thanks for the answer, that makes sense.
jdennis
Also for the doors.

Note that on an S or K set the brakes are electrically controlled.  Not sure if there is a triple valve or not but if there is it is only a failsafe, not the primary application mechanism.  There probably is a triple valve so that the brakes are applied in the event of a train breaking up.

Not sure why you'd go from Bankstown to the North Shore via Circular Quay.  Just change at Central, unless you're dead set against getting on a crowded train and having to stand, enough that you'd spend 5-10 minutes avoiding it.
  jdennis Junior Train Controller

Also for the doors.

Note that on an S or K set the brakes are electrically controlled.  Not sure if there is a triple valve or not but if there is it is only a failsafe, not the primary application mechanism.  There probably is a triple valve so that the brakes are applied in the event of a train breaking up.

Not sure why you'd go from Bankstown to the North Shore via Circular Quay.  Just change at Central, unless you're dead set against getting on a crowded train and having to stand, enough that you'd spend 5-10 minutes avoiding it.
"simonl"


You probably would change at Central, however I was just clarifying that a lot of people come in from outside the city and change to North Shore line trains at Town Hall, hence why it is so busy in morning peak hour on platform 3.
  simonl Chief Commissioner

Location: Brisbane
Is it that busy at Town Hall #3 in the morning?  When I was passing there every day I don't remember it being that busy - not as busy as Central.  Videos posted online for the start of the Marshall trial don't show it being that busy either.
  bowralcommuter Chief Commissioner

Location: Asleep on a Manly Ferry
Also for the doors.

Note that on an S or K set the brakes are electrically controlled.  Not sure if there is a triple valve or not but if there is it is only a failsafe, not the primary application mechanism.  There probably is a triple valve so that the brakes are applied in the event of a train breaking up.

Not sure why you'd go from Bankstown to the North Shore via Circular Quay.  Just change at Central, unless you're dead set against getting on a crowded train and having to stand, enough that you'd spend 5-10 minutes avoiding it.
"simonl"


Well actually that's why I get off at Wynyard (via East Hills though), so I can actually fit on the train. I don't care about standing for any journey 20 minutes or under. Another reason is because I can go to Coles at Wynyard too.
  HeadShunt Chief Train Controller

Note that on an S or K set the brakes are electrically controlled.  Not sure if there is a triple valve or not but if there is it is only a failsafe, not the primary application mechanism.  There probably is a triple valve so that the brakes are applied in the event of a train breaking up.
simonl
Yes, they have both Westcode EP and Westinghouse automatic air brakes as a backup or if they have to be connected to a different type of train/loco hauled etc.
  FullSeries Assistant Commissioner

Location: Sydney, NSW
Also for the doors.

Note that on an S or K set the brakes are electrically controlled.  Not sure if there is a triple valve or not but if there is it is only a failsafe, not the primary application mechanism.  There probably is a triple valve so that the brakes are applied in the event of a train breaking up.

Not sure why you'd go from Bankstown to the North Shore via Circular Quay.  Just change at Central, unless you're dead set against getting on a crowded train and having to stand, enough that you'd spend 5-10 minutes avoiding it.
simonl
Kind of right.

The primary brake on any train is the Westinghouse Air Brake. It is failsafe. No other service brake is (Park brake is, but its not a service brake).
In normal circumstances. The driver manipulates the brake handle through 7 steps of brakes (A,B,C wires) a Release & Running position and an Emergency position.

Those 7 steps of brakes send, via a Decoding unit, signals to units on each carriage called a 7 step relay. That unit then operates valves inside the unit which draws air from the main reservoir and sends it into the brake cylinders. Approx 27/28 kpa per 'step' of brake. Ditto for releasing the brakes. Westinghouse comes into play when the Lockout Magnet Valve is denergised in the brake stand or for some reason or another there is a loss of brake pipe pressure.

The Main Res is charged by 4 compressors on an 8 car silver/tangara set. Set to come on around 650kpa and cut out around 850kpa. They are all synced so if one comes on, they all do.

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