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by disposedtrolley 1687 days ago
This appears to be quite an old document (2012 judging by some of the dates in the screenshots, and the network map) but fascinating nonetheless, thanks for posting!

I'd be interested in learning how the signalling tech has evolved over the years. There has always been a push by PTV (the government body responsible for public transport in Victoria) to establish a "turn up and go" timetable where trains depart often enough that you shouldn't need to plan ahead. One of the restrictions of the old signalling system was a fairly large minimum distance between trains that prevented frequent service. This caused some congestion, especially in the hub and spoke model of the Melbourne network where many lines converge to share tracks as they approach the CBD.
3 comments
sytringy05 1687 days ago
IIRC high speed signalling is coming with the Melbourne Metro trains (and the existing lines those trains will run through).

Replacing train management systems like this with new ones seems to be all but impossible, my brother in law worked on one in the UK that was designed, built and implemented and the controllers basically said "no thanks". It only got implemented when they rebuilt the UI and control panels to look like the old one.

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skissane 1687 days ago
> This appears to be quite an old document (2012 judging by some of the dates in the screenshots, and the network map) but fascinating nonetheless, thanks for posting!

Yeah, is this factoid - central Melbourne train signals being controlled by an emulated PDP-11 - still true in 2021? I don’t know. Definitely this is known to have been true some years ago but can anyone confirm if it remains true today? The construction of the Melbourne Metro requires new signals, which I assume would be controlled by a brand new control system not the old PDP-11-based system. But if you are going to introduce a new system for one line, wouldn’t it make sense to try to migrate the existing lines to it as well?

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sytringy05 1687 days ago
According to this web page - https://vicsig.net/infrastructure/signalbox/Metrol - it seems yes, it has been replaced.

> Train Describer replaced with TCMS in 2014-2016.

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jojobas 1687 days ago
The signalling tech is old as mammoth's turd, "boomgates down/trains crawling" is a normal occurrence on quite a few lines.
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