Thanks, Mal. I share your surprise.
I visited Church St on Friday 24 August and rode over the old track in a W. The need for renewal was obvious! I re-visited on Saturday morning when the concrete breaking was underway, but then had to catch my plane back to Wellington so did not get to see the new track going in.
Keeping rails to gauge with that design should be OK – it will be more laterally rigid than railway track, after all, and is only tangent construction – but I wonder if the compacted basecourse below the sleepers will have enough foundation strength in the long run. Time will tell!
I contrast that with the new Christchurch track, designed with Melbourne advice and using Ri57A rails supplied through Yarra Trams, which has reportedly come through not only the big 22/2/11 earthquake very well but also survived the pounding by huge trucks and demolition machinery since. That construction used two layers of concrete and extensive reinforcing.
It is almost as though Melbourne is field testing every conceivable variant of tram track design and can't settle on any of them. I wonder what the next re-lay will produce (and when/where it will be – nothing showing on the Yarra Trams website.)
Brent Efford
On 23/09/2012, at 8:21 PM, Mal Rowe wrote:
On 22/09/2012 11:21 PM, Tony Prescott wrote:
>
> Mall, apropos my comments on Gold Coast, I gather from these images:
>
> http://www.yarratrams.com.au/media-centre/news/articles/2012/first-photos-of-chapel-street-tram-improvement-works/
>
> that Melbourne doesn't use reinforcing in the concrete?
Hi Tony,
Melbourne seems to have a rather flexible approach to tram track construction.
The return to mass concrete to rail level in Chapel St took me by surprise.
I suspect that the choice was driven by shopkeepers wanting minimum time for street closure.
It seems that in this case they rely entirely on the sleepers - concrete pads with steel bonds between - to keep the rails to gauge and provide reinforcing.
http://tdu.to/ChapelSt_BC_26Aug2012.JPG
(The BC in the filename refers to Before Concrete!)
Mal Rowe - trackwork voyeur
<ChapelSt_BC_26Aug2012.JPG>