I bet the pipes are still there. No need to remove them unless they are in the way. Like Sydney tram tracks keep popping up out of various roads or appear when workers start digging, so might the pipes of Melbourne's high pressure water system.
What high pressure water system? Glad you asked. Eek, I am sounding like Brian.
George Swinburne, who later set up Swinburne Technical College in Hawthorn, along with his uncle, engineered a system of pipes and a water pump, possibly near Spencer Street, to circulate water under high pressure underground around the city, and the industrial areas of South Melbourne and North Melbourne.
The water pressure could be used to operate cranes on the wharves, wool presses, for firefighting and most importantly for lifts in buildings. Before the high water pressure was available to operate lifts, building heights were limited to how many stairs people were prepared to climb. The water pressure was even used in theatres to lift sets into place.
While other cities had similar systems, Melbourne's was said to one of, if not the, world's finest.
George's company, Hydraulic Service Power Company, under a sunset clause, was later transferred to Melbourne City Council and was renamed Hydraulic Service Power Department.
I would love to add a photo of a metal plate embedded in a city street bearing the initials HSPD, but I have never noticed any, although I believe there are still some around. Do let me know if you have noticed any and can recall where.
I believe there are still water powered lifts in Melbourne, but only powered by mains pressure, so they would not travel many floors.
Here is some info I have come across while looking for more information. I cannot vouch for its accuracy.
There was another pumping station below Dights Falls.
Originally the piston had to go to the depth into the ground of the building's height, so enormous holes had to be dug. A later system used gears and pulleys in conjunction with hydraulics, so such a deep hole did not need to be dug. The remains of some of the equipment can still be found in basements of many city buildings.
The digging of deep holes into the basalt was very difficult and expensive.
The system did not close until 1967.
Mains pressure lifts still operate in the Church of Christ Scientist building in St Kilda Road, that little church building next to the Army Barracks.
There was a total of seven miles of piping. (doesn't sound a lot to me)
A warehouse on the Victorian Heritage Register in A'Beckett Street has an operational mains pressure goods lift.
Somerset Place was a centre for Sci Fi fans in the 1960s. The McGills warehouse where Sci Fi fans met had an operational high water pressure lift. To operate, close the doors and just pull the rope set into a recess in the lift. To call the lift if it wasn't there, sing out loudly and hopefully someone will send it up or down. (This tells me it was a goods lift)
Just to wrap, our George Swinburne certainly was a high achiever. He had directorships of various companies around Australia, he went into state politics under the leadership of Tommy Bent and resigned soon after because of Bent's behaviour. He was involved in many areas of public service, including being a foundation member of the State Electricity Commission of Victoria. I could go on but it is easy to find out about him on the net. Suffice to say, George sounds absolutely marvellous.
Later edit: The church in St Kilda Road is a bit south of the Army Barracks.