Modern practice is to have the overhead support structure in two parts: a foundation of reinforced concrete with a flange connection at ground level and a galvanised steel mast bolted to it, generally well after the foundation is created. That is the design used for new railway electrification construction in Auckland and the current renewal programme in Wellington – and I am sure elsewhere.
Creation of the foundations on a length of railway takes place over a period of weeks, often with the line in service, and the fitting of the masts is done in a weekend block of line.
No reason why this methodology couldn’t be used for steel tramway poles as well – including reusing heritage poles with corroded underground ends.
Brent Efford – former fitter-welder
On 10/07/2019, at 4:25 AM, Mal Rowe mal.rowe@...> wrote:
On 09/07/2019 00:21, Greg Robinson wrote:
> Judging by what I have seen in Dandenong Rd and PallMall in Bendigo the centre poles seem to last about 100 years.
I'm sure that proximity to salt water reduces the lifespan. The pole pictured in the attached image had to be removed due to corrosion at the base not long after I made the pic.
Original poles were painted (usually with am aluminium paint) but not otherwise treated for corrosion resistance. Modern poles are galvanised steel.
I doubt that electrolysis would play a part; no-one with any sense would allow a 'hot pole' to stay in use.
Mal Rowe - by the sea in Saanich