Cable tray beside rail

 
  Braddo Deputy Commissioner

Location: Narre Warren
I have a question about the metal cable tray type things besides most suburban rail alignments.

What purpose do they serve? Are they used for signalling?

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  Gman_86 Chief Commissioner

Location: Melton, where the sparks dare not roam!
I have always assumed so.
  bevans Site Admin

Location: Melbourne, Australia
The tray carries power and communications in most cases.  If you are travelling on the train and you see blue cable where it is opened up that is FIBRE OPTICAL CABLE  The darker cable is signalling and power.
  Braddo Deputy Commissioner

Location: Narre Warren
The tray carries power and communications in most cases.  If you are travelling on the train and you see blue cable where it is opened up that is FIBRE OPTICAL CABLE  The darker cable is signalling and power.
bevans
Are you able to elaborate on that? What are the communications used for? What is the power being supplied to?
  bevans Site Admin

Location: Melbourne, Australia
I am not a railway specialist infrastructure guy but I have been involved in a lot of infrastructure deployment. The fibre cable is carrying communication services between locations.  These are the CCTV cameras at the stations, the button you press for the next train, the emergency button and the platform display.

Telephones and radio repeaters trackside. It would also connect the trackside infrastructure for signalling and track control back to the signal box or metro or vline control.  Basically the fibre network now (using ethernet over fibre) connects control points around the network to a centralised control system with displays.  Of course is the case in Victoria Myki systems also use ethernet to connect back to servers etc.

Think of the fibre network as a wide area network with ethernet ports at key locations which connect to ethernet port and networks and central locations.

Where it is a customer wanting internet or a railway signalling trackside box the data is carried via Ethernet to the central point.
  Braddo Deputy Commissioner

Location: Narre Warren
I am not a railway specialist infrastructure guy but I have been involved in a lot of infrastructure deployment. The fibre cable is carrying communication services between locations.  These are the CCTV cameras at the stations, the button you press for the next train, the emergency button and the platform display.

Telephones and radio repeaters trackside. It would also connect the trackside infrastructure for signalling and track control back to the signal box or metro or vline control.  Basically the fibre network now (using ethernet over fibre) connects control points around the network to a centralised control system with displays.  Of course is the case in Victoria Myki systems also use ethernet to connect back to servers etc.

Think of the fibre network as a wide area network with ethernet ports at key locations which connect to ethernet port and networks and central locations.

Where it is a customer wanting internet or a railway signalling trackside box the data is carried via Ethernet to the central point.
bevans
Thanks for your detailed reply. Very interesting. I assume the fibre is a fairly new development, how were things different before it was introduced, and do you have any idea when it was introduced?

Where is the CCTV tramitted to? Surely the network can not handle the hundreds of cameras that exist on every line?
  bevans Site Admin

Location: Melbourne, Australia
Thanks for your detailed reply. Very interesting. I assume the fibre is a fairly new development, how were things different before it was introduced, and do you have any idea when it was introduced?

Where is the CCTV tramitted to? Surely the network can not handle the hundreds of cameras that exist on every line?
Braddo

Fibre has been around for some time at least the last 20 years in the rail network. (I can check this) but the way voice and other systems have integrated with the fibre network is a matter of timing. If you have existing investment in copper based telephony you are only likely to leverage the digital communications system they installed post the copper networks.

In a digital world (even on NBN) voice is carried over networks not as historical ETSI signalling but as a SIP service (VOIP if you like) so handsets become different. This is an example of using optical networks.

You question about CCTV connections goes to the capacity of the CCTV system (something I know something about with railcams) and also the capacity of the network to carry the video from the station to the central viewing area where the video could also be archived.

This is opening up more detailed chatter on how optical capacity is provided and managed and I can talk about this if you would like.
  Lad_Porter Chief Commissioner

Location: Yarra Glen
Some of those conduits appear to be years old, decrepit, in some cases broken, with exposed cables and general appearance of neglect.  Are the ones like that still functional?

In the case of some major change to a line's geography, such as LX removal, are new conduits installed?

To what extent could physical cables be replaced by some form of wireless/wifi?
  ngarner Assistant Commissioner

Location: Seville
Prior to the fibre optic cables that Bevans is referring to these cable trunks had copper cabling to connect signals, especially where three position automatics were widely used, e.g. think suburban area. These being cut and stolen, for the copper in them, has caused major delays in the past and still does occasionally where the fibre network doesn't carry all of the services required and copper wire is in use.
The state of them is not a new thing as I can remember seeing cable trunking in terrible disrepair in various locations over the last 40 years, even in the 'good old days' of the Victorian Railways, when they had dedicated signal and telegraph crews that knew almost anything they needed to off the top of their heads. I would suggest that if you can see cabling inside ones like those that Lad Porter refers to then, yes, they are still in use; they certainly were in the 1980's when they were in that state as fibre wasn't a big thing then, if it existed at all.

Neil
  bevans Site Admin

Location: Melbourne, Australia
Neil thanks for your contributions.

So how does all this data get down one glass pipe and to the location it needs to get to?  How does the glass pipe have enough capacity to carrying all the CCTV video from 100's of railway stations to a room where people can see all the screens?

Converged networks allow voice, video, data and internet to travel over a IP (the internet protocol) from one side of the network to the other.

This is achieved by specialist equipment in the network.  Essentially the ethernet connection you have in your house is either 100 mbit/sec or 1000 mbit/sec utilising a LAN cable.  You can link of the optical network as the same just a long piece of LAN cable in its simplest form.

Optical Networks allow the carrying of ethernet (a protocol) across long or short distances whereas ethernet is limited to around 80 metres.

How does the data get form the station at say Cifton Hill to Melbourne (or wherever it goes)? the LAN cable connecting the CCTV unit at the station is connected to a network switch which converts the signal from electrical to optical and light carries the data to the egress of the network (based on the network address) where it is converted back from Optical (light) to electrical to a LAN cable.
  billjohnston Station Master

As an extension to this thread, the new facilities being installed along the Dandenong line, presumably  for the new signalling, include three runs of perhaps 50MM galvanised pipe. What is in these pipes that can't be placed into conventional trucking?

Bill Johnston
  billjohnston Station Master

0ops sorry "trunking"

Bill Johnston
  bevans Site Admin

Location: Melbourne, Australia
As an extension to this thread, the new facilities being installed along the Dandenong line, presumably  for the new signalling, include three runs of perhaps 50MM galvanised pipe. What is in these pipes that can't be placed into conventional trucking?

Bill Johnston
billjohnston

I find this interesting when you consider I have laid a lot of fibre myself in 50mm PVC and 100mm PVC piping buried.
  rwatts Junior Train Controller

Location: Adelaide SA
Railway corridors are useful for things other than just rail infrastructure. My former employer's redundant gigabit internet link came from fibres belonging to (then) ETSA Utilities (now SA Power Networks) along the conveniently adjacent Gawler rail corridor in SA.  

Perhaps less relevant, I previously held securities in the Ethane Pipeline Income Fund which owned the Moomba to Sydney (Botany) ethane pipeline. It travelled much of the way through the suburbs via rail corridors and had to be dug up and moved at one stage for track quadruplication works.

Richard.
  Lad_Porter Chief Commissioner

Location: Yarra Glen
"Railway corridors are useful for things other than just rail infrastructure....."

At some points along Melbourne Metro lines, additional power cables are strung up high on the overhead stanchions, usually in sets of three.  Do these have a railway purpose, perhaps taking power to the next substation, or is the power provider just using the rail corridor for convenience?
  Op Kronos Station Master

"Railway corridors are useful for things other than just rail infrastructure....."

At some points along Melbourne Metro lines, additional power cables are strung up high on the overhead stanchions, usually in sets of three.  Do these have a railway purpose, perhaps taking power to the next substation, or is the power provider just using the rail corridor for convenience?
Lad_Porter
Yes these are responsible for taking the ~22kV AC from the electricity provider to the next substation to be converted into 1500V DC for the overhead.
Note: My understanding is that Metro is responsible for managing the ones strung up on overhead stanchions not the electricity provider.
  bevans Site Admin

Location: Melbourne, Australia
"Railway corridors are useful for things other than just rail infrastructure....."
Lad_Porter

NextGen Networks have fibre optical cable between Adelaide and Perth in the rail reserve.
  historian Deputy Commissioner

As an extension to this thread, the new facilities being installed along the Dandenong line, presumably  for the new signalling, include three runs of perhaps 50MM galvanised pipe. What is in these pipes that can't be placed into conventional trucking?
billjohnston

Nothing.

They are always trying to find a better trunking alternative for cabling. One that is cheaper to install, will not disintergrate so quickly, will protect the cables better from the less photogenic suburban wildlife (*), and/or will not be knocked flat by errant track maintenance machinery. Or at least that's the hope. They're always disappointed Smile

Around Caulfield they are using chunky black plastic boxes that can be placed at ground level or buried to lid level.

(*) rats
  historian Deputy Commissioner

Neil thanks for your contributions.

So how does all this data get down one glass pipe and to the location it needs to get to?  How does the glass pipe have enough capacity to carrying all the CCTV video from 100's of railway stations to a room where people can see all the screens?

Converged networks allow voice, video, data and internet to travel over a IP (the internet protocol) from one side of the network to the other.

This is achieved by specialist equipment in the network.  Essentially the ethernet connection you have in your house is either 100 mbit/sec or 1000 mbit/sec utilising a LAN cable.  You can link of the optical network as the same just a long piece of LAN cable in its simplest form.

Optical Networks allow the carrying of ethernet (a protocol) across long or short distances whereas ethernet is limited to around 80 metres.

How does the data get form the station at say Cifton Hill to Melbourne (or wherever it goes)? the LAN cable connecting the CCTV unit at the station is connected to a network switch which converts the signal from electrical to optical and light carries the data to the egress of the network (based on the network address) where it is converted back from Optical (light) to electrical to a LAN cable.
bevans

All modern communications infrastructure just treats communications streams - voice, video, signalling data - as streams of binary data. The actual cables are pretty much irrelevant - fibre, coax, twisted pair, wet string - you just put the appropriate data terminating boxes at each end that turn the binary data into however it is encoded over the cables and back again at the other end. It's even the same if you don't have a physical cable - the data terminating boxes just turn the binary stream into a radio signal and back again at the other end. The boxes also handle the protocols that run over the cable to worry about packetisation, addressing and error recovery. You then plug the cables together with routers and run other protocols over the top to deal with routing your bitstream from one end point (CCTV camera, signal, telephone, interlocking) to another.

It's technically complex, but completely off-the-shelf technology. It doesn't matter if you are building the NBN or a signal control system, it's all the same.

Incidentally, the actual protocols are ancient. Ethernet is 40 years old this year (in its commercial form, it's 47 if you count from its invention). The protocols above the link layer - TCP/IP - date from 1974. Network engineers were gods in those days - Vint Cert, Bob Kahn, Robert Metcalf, David Boggs.
  historian Deputy Commissioner

Thanks for your detailed reply. Very interesting. I assume the fibre is a fairly new development, how were things different before it was introduced, and do you have any idea when it was introduced?

Where is the CCTV tramitted to? Surely the network can not handle the hundreds of cameras that exist on every line?
Braddo

Orginally the CCTV cameras at stations went nowhere. The feeds were taken back to a bank of VCRs housed at each station. The cleaners used to swap the tapes over every day or so. If there was an incident, someone went down to the station to pull the tape and everyone hoped that it wasn't worn out.

About a decade ago they revamped the CCTV and converted it all to digital sent over a new communication network. The feeds now go back to control rooms at the premium stations. The station staff can pull up individual feeds, or it just cycles through the feeds. It's all still recorded, of course, as it's relatively unlikely that anyone will be watching when something interesting happens.

The bandwidth required for a single video feed is nothing these days. Think how many simultaneous Zoom meetings are being held during Covid-19 lockdown in Melbourne.
  historian Deputy Commissioner

The tray carries power and communications in most cases.  If you are travelling on the train and you see blue cable where it is opened up that is FIBRE OPTICAL CABLE  The darker cable is signalling and power.
Are you able to elaborate on that? What are the communications used for? What is the power being supplied to?
Braddo

Signalling equipment. Every signal needs power. Every set of points. Every relay box. Every track circuit.

If you read the technical papers of the US signal societies, power distribution has been an abiding interest from before 1900.

When the VR electrified the suburban network, the signalling power supply was also used to supply lighting to suburban stations. The flickering was noticable at night as Newport generated 25Hz AC. They didn't move to SEC power until the '50s or even later.
  historian Deputy Commissioner

"Railway corridors are useful for things other than just rail infrastructure....."

At some points along Melbourne Metro lines, additional power cables are strung up high on the overhead stanchions, usually in sets of three.  Do these have a railway purpose, perhaps taking power to the next substation, or is the power provider just using the rail corridor for convenience?
Yes these are responsible for taking the ~22kV AC from the electricity provider to the next substation to be converted into 1500V DC for the overhead.
Note: My understanding is that Metro is responsible for managing the ones strung up on overhead stanchions not the electricity provider.
Op Kronos

Remember that the VR started electrification work long *before* the SEC was established and even when it was nearly finished the SEC were only just getting Yallourn on stream. (A long time ago I remember my grandmother refusing to believe me when I told here that the line had been electrified in 1923 - "We didn't even have electricity in Goulburn in 1923".) There wasn't an electricity distribution network for the VR to plug into.

A very major part of the electrification works was the construction of a power station (Newport, later Newport A) and a substantial 22KV power distribution network to get the power to the substations. This was underground in the inner city and via aerial cables along the tracks in the suburbs.

The suburban distribution network is still partially intact; it's just fed from the former SEC network now.
  bevans Site Admin

Location: Melbourne, Australia
Whilst on the subject of power and management in the rail network there is a video of one of the last remaining and working Mercury Arc Rectifier probably in the world.  One of these was also installed at the Burnley Substation according to my sources.



https://www.youtube.com/watch?v=tiL9sLI5P98

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