Meyer Central Corridor: Sydney geology, infrastructure choke points and the rightful "King"

Sydney topography and infrastructure
Sydney's infrastructure development in many ways is a product of it's geology.  The Central Corridor proposed by Meyer (comprising the Dual CBDs of Parramatta + Sydney and the corridor within the inner west & eastern suburbs surrounding these CBDs) has the highest density of transport infrastructure in Sydney in large part because it is situated on the flat Cumberland plain on which it has been easy to build roads and rail, in the early days of Sydney's growth.  In contrast, the dominant geological feature of Sydney's northern suburbs is the Hornsby plateau, which is a sandstone plateau rising to 200 metres above sea level within the urban area and dissected by steep valleys such as the Lane Cove River valley.  These river valleys are major impediments to construction of transport infrastructure:

Map 1: 8am peak hour Google Maps traffic congestion
Note purple circles showing how Sydney's major river valley barriers and chokepoints lie in the Northern Suburbs

Meyer Central Corridor: Dual CBDs = Sydney's Manhattan

The previous post examined Bob Meyer's (Cox Architecture) Central Corridor, and identifed it as the "infrastructure giant" of Sydney, having triple the heavy rail/light rail density & a hands-down hero vs zero freight rail/ferry service superiority to the competing Global Economic Corridor (even after construction of NWRL & Second Harbour Crossing).

This post examines the Meyer Corridor population densities, and compares it with other global cities like Hong Kong and New York.  We start by looking at the local government areas (LGA) contained within the Meyer Corridor (the year 2011 data comes from Census, year 2016 & 2031 data are NSW Department of Planning projections):

FROGS Sydney 2051 Forum: Meyer's Central Corridor as "Extended CBD"

Yesterday, I attended the FROGS (Friends of Greater Sydney) forum, looking at an Action Plan for Sydney 2051.  A number of transport, urban planning, business and community delegates were invited to this forum and some really good ideas were explored.  Presenting at this forum were David Adams of Stratigex and Bob Meyer of Cox Richardson, and a workshop was then held following on from these presentations.

A idea that captured a lot of people's imagination at this forum was Meyer's concept of a Central Corridor for Sydney that incorporates Parramatta CBD and Sydney CBD as dual anchors at the western and eastern end respectively.  Meyer's conception of this corridor was to place it as the epicentre of knowledge jobs, in which agglomeration and geospatial proximity could be facilitated by intensive transport investment so that it would be possible to travel easily across the entire corridor within 20 minutes.  A map of this corridor and the surrounding hinterland is shown below, with the Central Corridor marked in yellow, with then the remainder of Greater Sydney conceived as a hinterland, with subregions to the North, Northwest, Southwest and South.

SRT Central station: Airport line becomes branch of SRT?

This is now my third post on speculation about the design of SRT CBD stations, with my previous posts looking at Pitt St and Martin Place stations.  This post will look at the SRT Central station.

My best guess for how the SRT Central Station would work comes from the NSW 2007 Infrastructure SEPP, which reserved a corridor for the CBD Metro.  Although the CBD Metro ended up being cancelled, it's core idea of a segregated single deck system was subsequently modified and adapted and survives (controversially, but also cautiously given a tick of approval by others) in today's NWRL and the planned future stages of SRT.

So what does the old CBD Metro corridor say about a possible SRT station?  Firstly, it is likely to be built on the adjacent west side of Sydney terminal, making interchange with inter-city & country trains from Illawarra/Blue Mountains/Central coast quite efficient:

SRT "super-station" at Martin Place/St James is best use of existing high "sunk cost" infrastructure

My last post described the "super-station" concept where a station on one rail line can join up two previously separate stations of other train lines, so as to form a "super station" that allows interchange across three separate lines (eg. London's Crossrail at Liverpool St/Moorgate).  These super-stations are also quite viable construction-wise, as they leverage existing surface access, thus minimising expensive surface excavation of large station boxes.  As seen in the Crossrail station diagram below, most of the Cross rail super-station is formed by TBM bored tunnels, and needs only relatively small open cut concourses, that extend/use existing station facilities:

SRT geotech studies and CBD "super station" design

Geotechnical work on the SRT has commenced, as widely reported by newspapers and TV channels.

This would allow refinement of the exact route, which according to information provided to date will have CBD stops at Martin Place, Pitt St and Central.  It is useful to think about the design and location of the CBD stations, as these stations will have the greatest influence on SRT capacity and effectiveness.

High speed rail blogger/engineer Zoomwhoosh has come up with some interesting ideas on how the Pitt St station could work.  His idea is for the SRT Pitt St station to have a design and location that follows on from the aborted CBD Metro design, albeit with some lengthening of the station to accommodate a minimum of 8 car trains.  He also proposes building a concourse and station box for a future Parramatta-CBD express rail, as some form of concourse between Pitt St and Town Hall is needed anyway to allow passenger movement between these two stations.  Importantly, distance between Town Hall and Pitt St is just right to fit in a ~200m long station to join up these two stations: