Christchurch - relatively modest cut & cover tunnel could bring commuter and long distance trains right into city centre

A diesel hybrid train in Japan - but under Christchurch city? There IS an option....

This essay © David Welch 2022  [updated from orignial published on this site © 2018 ] 

"Christchurch Railway Station is too far away from the centre of the business and commercial area".  Historical research reveals that this was a complaint as far back as 1863! 

Strong criticism was expressed even before the city's first station opened on "South Belt" (now "Moorhouse Avenue"). Calls were made for horses to be used to pull the detached railway carriages (arriving from Heathcote wharf) up into the central business area. 

 As researching old newspaper sites will reveal, the distance of the railway station from the centre of the city it has been constant Canterbury grievance for 159 years. In 1993, and the then privatisation of rail, the city's “central” passenger station was moved to an even more distant location, at Addington.

Any suggestion of re-instating a regional commuter rail network with the existing station falls at THIS, the first huge hurdle: -  If virtually all of the passengers have to transfer from the train service to buses to access the city centre, it negates any time saving efficiency and renders the whole system too clumsy and expensive to be attractive.

 Car usage in the modern age has created a cultural expectation of door to door travel with immediately adjacent parking – this has becoming increasingly difficult to achieve in a congested city, but it is still the gold standard.

However, subject to further investigation, there appears to exist an unique opportunity for Christchurch to bring commuter rail services right into the heart of the city and to do so at a relatively low cost by world standards. Train services from Invercargill, from Picton, from the West Coast and Southern Alps, as well as commutor services from greater Christchurch - Amberley and Rolleston included - would come right into the very heart of the city. 

Equally people in inner city apartments ans suburbs could access employment across the crescent spread of greater Christchurch - the big banana of tomorrow. Such a move seems likely to boost central city revival and increase investment in new businesses, inner city housing and employment  significantly. Not least, there appears a excellent chance to link rail access directly tofro the new 30,000 seat stadium and exhibition centre Te Kaha. 

Auckland's cut and cover tunnel project

Inspiration is offered by the construction of the [2019 figures] $4.4 billion City Rail Link in Auckland, a 3.5 km underground loop line from the city's main station, Britomart,up to Mt Eden and the western rail corridor. The first kilometre of of the Auckland underground system, from Britomart is a "cut and cover" tunnel just below the surface. Most of the remaining underground will be bored at a deeper level - this is a necessity because the Mount Eden  part of Auckland is situated on volcanic rock formation with hills too steep in their incline to allow the railways to follow exactly below surface slopes.

Of particular interest, is the way the City Rail Link follows the alignment of Albert Street through central Auckland, a huge trench being dug out (one side of the road at a time) and then lined with reinforced concrete walls, creating two parallel tunnels. When a concrete ceiling is placed on these, and the various underground services are reconstructed, the road above will be restored as it is now. This concreted trench tunnel will allow commuter trains to run in both directions some metres below the street.

At a quick glance it seems surprising that such a massive excavation can occur right in the midst of large tower buildings, but it is of course common to excavate large holes for the foundations of high buildings, with one high rise excavated right beside another. 

An added requirement, and an often huge cost of tunnelling under established streets, is the construction of new alignments for other underground services, such as water pipes, sewerage, electrical cabling, stormwater drains, etc., along or across the streets.

A cut and cover railway tunnel into the Christchurch central area

I believe, if the political will was there  it would be possible to build a similar 'cut and cover' reinforced concrete tunnel, offering two parallel railway lines (possibly more at station points) and three simple underground stations, starting from a point near the current Christchurch railway station at Addington and continuing right into the very commercial and business heart of of central Christchurch.

The cut and cover tunnel suggested here could be built across - that is to say well beneath - Hagley Park, then under hospital corner (with an underground station there),  and continue to an underground railway station complex, with escalators up into the Bus Exchange and Colombo Street, and Hoyts Cinema complex, and primary central city retail area. The lines would then  continue to Te Kaha, the new sporting arena and festive events etc, arena intended to hold 30,000 plus.  and an underground terminus at, near or under this new sports stadium and exhibition centre between Madras and Barbadoes Street.

This scenario would require the purchase of part of the former stock sale-yards site, in Deans Avenue, now demolished and currently in temporary use as a one level car-park for the hospital, served by shuttle buses. All other land required I believe is in the public domain, requiring no land purchase costs or legal disputes.

It goes without saying there are multiple synergies here, not least linking the main trunk rail lines to Picton, Dunedin and Greymouth, and past the  South Island biggest hospital, and directly to the retail centre of Christchurch and bus transport exhange.

I have included below some ballpark figures for likely costs. Noted; these are not minimised to be appear more palatable to potential opponents, but broadly realistic in terms of similar projects in other cities. Large "game changing" and city building infrastructure of this nature, designed for long term benefits into the billions, can not be built by enfeebled suggestions of reusing third-hand cast off rail units ex Auckland, or (most bizarrely, as was suggested some years ago) creating a "temporary commuter rail system"!  

Rather costs agiven are broadly calculated in reference to similar projects in Auckland and Wellington, obviously this can only offer a very rough guide, but not one I hope completely amiss.

A tunnel under Hagley Park

It is envisioned that from the main trunk line between Addington and Riccarton Road (running parallel with Deans Avenue) two separate lines would branch off heading eastwards in to Hagley Park. One line would offer access to trains tofro Rangiora and north, and the other access to trains tofro Rolleston and south. Both these lines would follow a gentle downward sloping curve that would take trains under Deans Avenue and then under Hagley Park. This might require a slight rise to carry Deans Avenue over the tunnel entrances, or even a slight landscaped hill at the edge of Hagley Park, to allow a sufficiently graduated slope into the two railway tunnels. Once under the park these two curving tunnels would come together and become either a straight double-track tunnel, or two parallel tunnels, and head underground towards "Hospital Corner."

                  

                 Section of the cut and cover tunnel under Albert Street in Auckland nearing completion

                 photo courtesy of CRL

Tunnelling costs around the world, are greatly effected by the surface being cut through but there will be no unexpected hard rock mass under Hagley Park or central Christchurch. Drainage will no doubt be a factor, but building a cut and cover tunnel through shingle or soft ground across the open space of Hagley Park, is likely to be cheap tunnelling by any world standards. Allowing for complex railway junctions and all safety and ventilation aspects, on roughly similar projects, I'd guess cost for this section, probably under $70 million.

After completion of the construction phase of the cut and cover tunnel, the earth and grass would restored over the tunnel ceiling perhaps three to six metres below ground level. There would be no obvious change in the appearance of Hagley Park, other than a possible replacement of a few large trees whose roots would otherwise interfere with the tunnel. There has been public resistance to past proposals to build car park facilities under Hagley Park – but that concept, by its very nature, feels a violation. I would imagine this option, intrinsically fostering a “greener” more pedestrian friendly Christchurch, would encounter a much smaller rump of opposition.

A station at or near hospital corner

At Hospital Corner, the tunnel would pass under Hagley Avenue and into - and of course under - Tuam Street  with obvious potential for station at this point. The existing under-road pedestrian tunnel for hospital staff and a separate public pedestrian tunnel could link to the hospital and outside areas to platforms on both sides of an underground station, as well as to the bus stops above.  Modern underground stations typically have glassed off tracks, the platform length doors only opening when trains are actually stopped, preventing accidents, suicides, graffiti etc.

The "Hospital Corner" station would offer easy walking distance access not only to the hospital and medical school, but also to the planned Metro Sports Facility, Hagley Learning Centre, Hagley Park and the cricket oval, the Botanic Gardens and boatsheds, Museum, Arts Centre, Christs College, City Council buildings and to the office blocks and apartments west of the Avon.

A tunnel under Tuam Street to city centre station beside Bus Exchange

Passing under the alignment of existing streets will be considerably more expensive than tunnelling under open park land. This said, the length of track suggested here, from hospital corner to the suggested terminus is only slightly over one kilometre. Based on the one kilometre of cut and cover tunnel being cut under Auckland's far more intensely developed lower Queen Street and Albert Street (where large storm water works etc. also had to be shifted) I suspect that such distance in Christchurch might be constructed for about $200 million.

      

            the cut and cover tunnel up Albert Street in 2018 before road reinstated   courtesy of City Rail Link

Two simple underground through-stations with above ground entrance foyers, one at the Hospital, and one near Colombo Street, linked into the Bus Exchange by lifts and escalators, together might add another $70 million. 

These stations are fairly close together, so the trains between them would virtually just slide along at under 20km, but link directly to the different mass catchments, the second here including direct access to all Colombo Street and Cathedral Square. 

A third station and terminus, only three blocks further east is also suggested and would be needed, if only for operational reasons, anyway.

Central city rail tunnel continues to Te Kaha Sports Stadium and Exhibition Centre

The terminus could be about 400 metres further along under Tuam Street between Madras Street and Barbadoes and directly beside or even directly underTe Kaha giant sports stadium and exhibition centre. This might also sensibly include an underground stabling area, four to six platforms/tracks wide, or similar. 

This stabling could create significant operational economies as overnight night, or during the off peak period during the middle of working days, some of the trains could be parked and internally cleaned here. This is effective in operating terms as in the evening rush hour extra units are already in the city centre to bloster the outward rush hour traffic.

Constructing a couple of island type platforms with stairs and escalators to the stadium above could also allow various units, and longer locomotive pulled trains, to load simultaneously (including those for Dunedin and South Canterbury and Rangiora and Amberly  etc.)  following major sporting events, or during large exhibitions and festive events held at the stadium.  With many people wanting to wine and dine before and after the game Friday and Saturday trains could be running not only before and immediately after events but into the early  hours as well, a significant additional income stream to workday commuter traffic 

This station alone might cost another $70 million, although possibly it might be built and leased back by the stadium builders or operators. Potential savings in terms of excavation, pile driving, stadium/station pillars etc. might also be achieved by simultaneous construction.

Or alternately it may be under a companion parking building or surface level parking or lawns.

The Central City bus and rail station and a Madras/Barbados Terminus, in the scenarios here would offer easy walking access to the Justice Precinct, the new Hoyts 7 Cinema complex, the Bus Exchange, Ara (Polytech), Catholic Cathedral College, High Street and Cashel Street Malls and Laneways and only slightly longer walking distance, Cathedral Square and other parts of the central city. 

The area of the central city south of Cathedral Square has always had more capacity to form the busiest shopping, commercial and business part of central Christchurch - the suggested railway line conveniently intersects this primary activity zone.

[ NOTE station symbol near Moorhouse Ave is intended as sample  - not return to former station  site!!]

Hybrid diesel or hybrid electric trains, an obvious option

Obviously it is not suitable to use diesel power in busy underground tunnels. Electrification of Auckland railway cost $1.3 billion, not counting the new trains. The huge cost of electrifying all the Canterbury lines could be postponed for many years, or even permanently avoided by using hybrid passenger rail units and locomotives. These systems can operate with batteries linked to either standard diesel, or with overhead as powered electric trains. When running only on the batteries these locomotives or units are capable of pulling surprisingly large loads (over a thousand tonnes) over reasonably long distances, typically 60-100km. Several international railway vehicle builders now offer hybrid options. Indeed, Auckland Transport had planned to purchase 17 hybrid such hybrid electric units, until both the main political parties announced they would fund overhead electrification of the line between Papakura and Pukekohe.

The added chance to recharge batteries from an overhead power supply, every time, whilst running through the central city tunnels, or while parked at mid-day or overnight in the underground terminus, would clearly support such a system and ensure smoke and exhaust free operation in the tunnels, as well as quieter running trains as far afield as Rolleston and Rangiora, perhaps using diesel only beyond these points.  A fleet of, say 20 hybrid 140 seat passenger units, and several separate hybrid locomotives to shunt or pull conventional coaches (including dedicated cycle coaches on the main peak hour trains) - the minimum rolling stock needed to operate a sufficiently frequent service (given population and regional distances) - would probably cost about another $300 million.  

   

                               

a cycle carriage on a New York commutor train for those using cycles at both ends of their commute

                 

Copenhagens  'S' Train, including specialised cycle carriages  - courtesy of ITF

The general upgrade of railway across the city to allow for commuter rail and (and no doubt a chance to improve freight movement) would also be needed, this might absorb another $200 million, and might include over-bridging of rail tracks on some arterial roads and the building extensive car parks for commuters in outer suburbs and towns. Wellington railway has over 4000 such car parking spaces across the region, Auckland is struggling to create more. 

The tired old equation “public transport versus private car” still occurs in local newsmedia or politician speeches; - it does no justice to “park and ride” character of public transport  in many modern systems serving sprawling built-up metropolitan areas. (Boston for example has over 46,000 park and ride spaces – in other words 46,000 cars that don't get driven into the city or on congested roads). Secure bicycle day-storage systems would also be necessary at most suburban stations.

Local and Regional authorities to meet only half the cost of construction?

This circa $1 billion seems (and is) a huge amount of money, BUT on the precedent of Auckland and Wellington it might be expected that central Government would provide a $300 million loan for purchasing modern rolling stock. This is then repaid over time, as part of annual operating cost by the regional authority overseeing railway operations. By similar precedent, in Auckland and Wellington, central Government could be expected to fund about half of the actual construction costs, either met directly by central government and its agencies, or  in some aspects as part of KiwiRail's infrastructure budget. In these circumstances the city/region would be looking at  financing about $350 million in a project that will hugely lift Christchurch's status and attraction to new residents, visitors and tourists.

That greater Christchurch should seek about $350 million in direct Government support ALSO seems to be nothing but a bit of "commutor rail equality" and “balancing of the books”, given the huge investment by Governments (both Labour and then National) in commuter rail in Auckland and Wellington in the last 20 years, presumably with a significant portion of that financed derived from Canterbury taxes.

Both these cities have had an obvious strong case for public transport infrastructure funding from taxpayers, Auckland because of its larger size and rapid growth, Wellington because pf its geography, its restricted central area and bottleneck approaches. This said, the population of greater Christchurch is actually larger, faster growing than that of Wellington region and the  extended metropolitan area population of Christchurch is expected to surpass that of greater Wellington region over the next 25 years. (NZ Transport Agency Stats - circa 567,000 versus 527,000)   

Extremely rapid growth of both Rangiora and Rolleston, and adjacent areas, makes it clear tomorrow's “greater Christchurch” will, in effect, be something of a banana shape extending over 25 kilometres northward and over 25 kilometres southwards. 

Exactly the sort of profile best met by commuter rail.

 

I think this concept put forward here is a huge game-changing possibility. As such it deserves a full multi-discipline professional feasibility study of the core concept. 

Used to assist this, the promised $100 million in Canterbury commuter rail funding by the Labour Government offered [in 2018]  might then go far further than anyone ever dared.

Extras
For (fairly historic) info on historic Wellington expenditure "Take the money and Run"

For the gross imbalance of NZ taxpayers money invested in Auckland (2013) Government asks New Zealand to massively subsidise Auckland transport?

Greater Christchurch to have a potential commuter base 80,000 people more than Wellington region within 25 years, or see [pages, see right hand column] 

City Rail Link (CRL) tunnels — City Rail Link This site offers a short You Tube illustrating how the cut and cover tunnel was made under Albert Street in Auckland. 

This site offers a walk through the cut and cover tunnel

Since the original blog was posted the new Labour (Plus) Government has announced  - Regional Rail for Canterbury 'On the table"

For the latest government plan to spend $14.4 billion  on a  light rail link serving Auckland Airport-city and (at a guess) about one sixth of the Auckland residential population catchment  Auckland Council not in a 'financial position' to help pay for $14b light rail | Stuff.co.nz