It is not as though the problem of getting fixed truck trams around tight curves hasn't been dealt with in the past nor have solutions adopted by highly experienced and capable engineers not been recorded by Technical Journals.
NSW Tramways had a long history of operating 4 wheel trams (C, D, E,J, and K classes) between the 1890s and the 1950s with a number of 4 wheel service trams enduring until the final system shutdown. For many years these trams operated, often as coupled sets, on the tightly curved and steep Bondi via Belluevue, Watsons Bay (for 30+ years an exclusively 4 wheel tram service) and North Sydney lines.
Other Australian systems also had many examples of 4 wheel trams.
The attached page 424 "Bradfield on Electric Tramways"extract from
*Electric tramway : The Spit to Manly, N.S.W. / by John Job Crew Bradfield*
shows the 'easing of gauge' adopted for decreasing radii of curves and also for different rail cross sections adopted as system standards. Most outdated of course as it had nothing to do with real (heavy) railways!
Regarding the "institutionalised extablishment" I recall attending a presentation by a leading practitioner of this group as he expounded on CSELR light rail track. When questions from the floor were invited I asked if any consideration had been given to easing the gauge. He first appeared non plused, then followed the "Pesant, I am the expert consultant, put down.
Unfortunately one of attendees in the audience piped up "I work for XYZ concrete sleeper manufacturers and we have made easing sleepers to special order for Melbourne", the Chair of the meeting immediately called for the next presenter to present a paper on a different subject!
One could also note that after their sterling work on the CSELR WSP/Parsons Brinckerhoff were commissioned by TfNSW to undertake similar work on the Parramatta Light Rail.
On 2/08/2021 2:42 pm, TP wrote:
> As far as I know, there is no curve on CSELR less than 25 metre radius which is the generally accepted minimum for a tram with fixed trucks, though it by no means immunises the system and its trams from damage, especially when there are quite a few curves and many trams, as on CSELR. Many of these modern light rail systems are basically long runs of straight lines (typical grid city layout, which Sydney isn't), with the occasional turn to navigate. A fixed truck tram is simply unsuitable for a line profile that has frequent curves. New systems like Adelaide, Gold Coast and Canberra are examples of systems with long straight runs and only a rare corner or curve, so they get by with the fixed truck trams. None of Sydney's three systems has significant straight runs.
> So many mistakes and with little prospect of being rectified, as I see that the new light rail mob with their heavy rail background have become the institutionalised establishment , complete with their own prefessionally internalised annual conferences where they can share their lack of knowledge with each other, unchallenged by those "outdated" folk from legacy systems. Though, it is true that Melbourne professionals do get along to these talkfests but, if they proffer any educational role, it doesn't seem to have any effect. I wrote a letter to TAUT about all this recently. Time to lift the game and not rest on laurels.