My recollections of platform lighting in Melbourne go back to the 1950s or thereabouts.
I stress that these are recollections so don't anybody take them as anything more reliable.
In the 1950s platforms were lit with incandescent globes housed under enamel steel shades. These globes (which I think were ES) were replaced when necessary by station staff standing on the office stool. These lights were on steel poles about every carriage length but station name boards were only on every second light pole IIRC. The diameter of the 'boiler tube/water pipe' used reduced at about half height.
The 1950s lights were replaced (in which order I don't know) by double tube fluorescent fittings and/or by a glass 'bubble' looking fitting with some gee whizz sort of globe.
More recently the big square fittings have been applied with perhaps differing types of globes over time. These fitting were placed on new larger diameter and taller poles at closer spacings I think.
Undoubtedly, the new square lights are a huge improvement on everything that they have replaced but suffer from what appears to be a dramatically shorter globe life and/or a significant failure rate of their switching arrangements. Whether this is due to the globes or some form of light/dark sensor used or simply due Metro's poor standard of maintenance I don't know but the end result is the same. I have often counted in excess of 10 defective lights at many suburban stations.
the VR electric lights were originally screw mount ( not bayonet mount , the Australian standard ) DC incandecsent lights powered from the VR Spotswood Power Station, which was built to power the 1500V DC overhead wires and was later transferred to the SEC / State Electricity Commission of Victoria .
The DC lights were then changed over to AC screw mount incandescent , and around 1959-1961 period the VR introduced its unique VR designed twin fluorescent tube light fixture which gave a good spread of light, was sealed and did not shine into the Driver's eyes.
There was a VR Newsletter article about these light fittings which I think were manufactured at the Spotswood Signals Workshop. ( I am happy to be corrected on this )
The VR design was still being installed into at least the 1970s. It is also correct that the VR only placed a station sign on every second lamp post in the Suburban Electrified Area , and the last lamp post at each platform end also did not get a station sign.
The VR white target with black lettering station signs, so typical of the Suburban Area , were large and usually easy to read , the long station names eg Middle Brighton, for example whose letters were a bit squashed up to fit the standard space , were readable and long lasting. Which is more than can be said for both the Met Green with white lettering, and the V/Line orange with black lettering especially, whose viewability at night or in inclement weather was , to say the least, marginal.
When Connex undertook to install the new Blue and White station signs to replace those near unreadable Met green with white letters station signs , a decision was made to equip every lamp post with a sign , including the very last lamp post on the platform ends.
Someone must have been required to physically check every new installation because Montmorency did not get new signage on the end lampposts , but this was rectified around a fortnight later.
Poor signage is a pet hate of mine , and Connex did the re signage properly in that every station was changed over, every lamp post equipped and the signs were readable at night in inclement weather , something which definitely did not apply to the Met green signs.
Connex should be given credit for seeing this through, because previously the re signage undertaken by both the Met and V/Line ( orange ) started of well but quickly degenerated to half heartedness as someone inevitably decided to save money by supplying lesser numbers of signs per location , which completely ignores what I would have thought was the obvious necessity of having signage that is readable from every carriage window.
Like Heihachi73 , I am surprised that the yellow sodium lights have not all been replaced with White LEDs purely on an operational cost ground, as yellow sodiums are very expensive to run compared to the white LEDs , and the later give a better night view compared to yellow sodiums.
In my view Victoria generally does signage badly, and VicRoads and its predessessors are a classic example of this.For example, on the M11 Peninsula Link south of C777 Frankston-Flinders Rd and heading in a northerly direction you pass a sign stating only "Glen Waverley xKm" , which conveniently ignores every suburb between Frankston and Glen Waverley !
The Western Bypass , though I think it has now been rectified, when heading in a southerly direction , once had a sign on the entrance to a curve before the over bridge that preceded the Tullamarine Airport turn off directing you to the left hand lane, which was just around the corner ! So unless you had travelled on that road previously and are already in the left hand lane you were pretty much guaranteed not to be able to make the left hand turn in time, and your next exit was many kilometres away.This was an 80kmph section of freeway. In more recent times I have travelled back from Geelong via the Bolte Bridge and the signage there is also not that good either.