Wellington Scoop

Trackless trams – claims that don’t stack up


by John Rankin
An international consultant has been telling Wellington to consider trackless trams, as a way of easing the capital’s congestion. How well do the consultant’s claims stack up?

1. They can carry 300 people. Really? Canberra’s light rail vehicles are a metre longer and the same width, with a stated capacity of 250 people at 4 standing passengers / m2. Has the consultant actually seen a trackless tram with 300 people on it?

2. They cost as little as a tenth of the price of light rail. Presumably in large part because “you just paint the lines on the road.” There are 3 main reasons light rail systems have a prepared road bed and rails:

– the road bed is zero maintenance for at least 25 years, so there is no disruption to service for road repairs
– underground utilities can be relocated, so there is no disruption to service because of utility line faults
– a high quality road bed with rails on sleepers delivers a high quality ride without damaging the road bed

Trackless trams on Wellington’s low quality roads would deliver a low quality ride, while requiring regular road repairs. Supposedly that’s not a problem, because …

3. The vehicle can deviate around obstacles on the track. In real-world transit operations, this is a bug, not a feature. If we look at cities overseas with on-street light rail, obstacles on the track very rarely disrupt service. So the trackless tram solves a non-existent problem. But having a vehicle that can leave the tracks tells every other vehicle on the road that it’s OK to park in the tram lane, because the tram can drive around you. If in doubt, see any bus lane in Wellington. Perhaps the real reason is trackless trams have to be able to navigate around road works, to repair damage the vehicles have caused or to get at underground utilities. When the trackless tram leaves its dedicated lane and mixes with other traffic, the service becomes less reliable.

4. They can be configured to run without a driver. This is a game-changer and a great feature. It breaks the tyranny of frequency, because you can afford to run a very high frequency service at very low marginal cost. However, I suspect the current state of the art is that you can have autonomous operation or the ability to navigate around any obstacle on the track, but not both.

5. Trackless trams would be perfect for Wellington. Would they? The practical limit for on-street operation is about 20 trackless trams per hour, giving a capacity of about 5000 passengers per hour in each direction. Using GW’s ridership figures and growth projections, if a trackless tram line opens on the railway station to airport corridor in 2025, it will be at capacity by 2030. What is the upgrade plan? Would we have to replace it with higher-capacity light rail and if so, how would we carry out the upgrade? To increase the frequency to 30 or more trackless trams per hour would require grade separation along large parts of the line, which would cost at least as much as building light rail in the first place.

Wellington would be wise to let somewhere else be the pioneer for trackless trams. I fear the reality is that you can have light rail quality of service or you can spend a tenth the cost of light rail, but not both.

For reliable, frequent, high capacity rapid transit, light rail still looks like the best option for Wellington’s station to airport corridor.

John Rankin is a spokesman for Fair Intelligent Transport (FIT) Wellington.


  1. mason, 12. May 2019, 3:50

    Trackless trams are basically just a bendy trolley bus, they will chew up the road surface and attract minimal people from their cars to public transport.

  2. Eric B., 13. May 2019, 12:38

    So “Steel wheels good, rubber wheels bad” John and mason?

  3. Mike, 13. May 2019, 13:40

    One of the problems with light rail is that so many projects never get past the planning stage as they are so expensive. Any light rail in Wellington will be quite a few years away so plenty of time to follow what is happening and whether some of the concerns are real or not.

    A key consideration not mentioned in the blog is resilience post earthquake. If initial construction is going to take years then reinstatement will probably be the same.

    Recent implementation of these vehicles in Belfast, Sweden and Barcelona resulted in immediate and sustained 20%+ increases in PT Patronage so I am not sure Mason is right.

  4. Keith Flinders, 13. May 2019, 14:24

    Mike: If you are worried about seismic damage to the light rail track, then look at what happened to the tram tracks in Christchurch 2013 and 2016 – virtually nothing. The main issue was building debris that fell across them and needed clearing.

    The Christchurch tracks were installed at a fraction of the cost per km. of the current grossly over engineered project in George Street, Sydney, and were in place in a fraction of the time.

  5. John Rankin, 13. May 2019, 14:50

    @Mike: interesting data about patronage growth. If Wellington experiences the same 20%+ growth, then a trackless tram system on the railway station to airport corridor will reach its maximum capacity within 2 years. What is the upgrade plan to handle further growth?

    To achieve the same carrying capacity as much higher capacity on-street light rail vehicles, trackless trams would need to run on a fully separated right of way, rather than on-street. This would allow a higher operating frequency than is practical on-street. Building a segregated system would likely cost more than building an on-street light rail line.

    However, a fully segregated transit line has a lot going for it. If we could build (and consent) a fully segregated trackless tram line for the same cost as an on-street light rail line, it would be worth close consideration.

    Trackless trams offer a potentially very attractive solution for places like Karori, where passenger volumes are too low to support an investment in light rail. I am unconvinced that they are fit for purpose on our busiest public transport corridor.

  6. greenwelly, 13. May 2019, 14:53

    @Mike, realistically 2027 (when the current bus contracts expire) would seem the obvious target date for any light rail/trackless tram…..

    To facilitate any new “core” service, bus routes would have to be significantly rejigged to a) allow the new service space on CBD streets (i.e trams and buses on Manners or other narrow streets would be problematic), and b) to act as feeders for the new high-frequency/capacity spine(which would likely require the end of long cross town routes..)

  7. Michael Gibson, 13. May 2019, 16:13

    I don’t see why we would have to wait for the contracts to expire in 2027 before we have new ones.
    For such a mess to exist, the present contractors in Wellington City must surely be in breach of their respective contracts and the breaches are visibly big enough to warrant cancellation. I realise that the “shortage-of-drivers” excuse is convenient for the Regional Council (because they have run out of other excuses) but that is the contractors’ responsibility. It simply serves as an extra reason for cancelling the contracts and restoring the old timetable. If there is any excuse about PTOMs or whatever then the new government can fix it at the drop of a hat.
    In other words: cancel and restore!

  8. Chris Baxter, 13. May 2019, 19:03

    Michael – I hope you never get to be in charge of our Nation’s cheque book

  9. Tom, 14. May 2019, 12:13

    Isn’t the technology secondary to the corridor?

    The most important part would be to agree and protect a corridor for a big box thing to traverse, then, procure and implement the best big box thing that suits the designated corridor and the ridership, underground infrastructural, and other requirements?

    Seems a bit cart before horse otherwise (or train before track)

  10. John Rankin, 14. May 2019, 14:25

    @Tom: yes. I have long suggested that LGWM consider “technology-neutral procurement” — specify the business requirements the “big box thing” needs to meet and invite proposals for how these requirements can be met. In a requirements vacuum, proposals like trackless trams come along to fill it.

    If we do this, we quickly conclude that over the life of the system we need to plan for up to 10,000 passengers / hour on the railway station to airport corridor. What is the best way to deliver this? Can trackless trams do so?

  11. greenwelly, 14. May 2019, 14:48

    @Tom, yip, a finalised corridor, (especially the CBD route) is a major pre-requisite. Which is why I’m not hopeful that LGWM will actually have much of its programme “front loaded” and will require Wellington to “re-engage” with another “spine study” or similar over the next couple of years.

  12. Kerry, 15. May 2019, 12:22

    The photograph above is reasonably close to a plan-view, and the length of each section can be worked out reasonably accurately, from the known width of 2.65 m. I make it about 36m overall.

    The light rail vehicles proposed by FIT are the Siemens Avenio, 63m long, and Siemens give a capacity of 370 when loaded to 4 pass/sq m. Subtract 3m from each, to allow for cabs at both ends, and the passenger lengths are light rail 60m, TT 33m. Trackless capacity is about 200 at a reasonable loading.

    If TTs can be lengthened to five sections, 50m, the capacity will be about 330, not too bad, but in Wellington the exiting length won’t do.

  13. John Rankin, 15. May 2019, 13:59

    @Kerry: I think you misread the capacity of Siemens vehicles. A 2.65m x 63m Avenio has a capacity of 470, not 370. Hence I stand by my claim that the capacity of the trackless tram as described is about 250 people. Your conclusion that “in Wellington the exiting length won’t do” still stands.

  14. Helen, 15. May 2019, 14:21

    John & Kerry – I like sitting down! Remember when GWRC took seats out of the buses to raise carrying capacity? Sardine transportation is not for me. I remember the quiet, smooth and economical trolley buses that fitted Wellington so well.

  15. Kerry, 15. May 2019, 15:04

    John: correct: my apologies

    Helen: I like sitting too. The example vehicle has only a quarter of passengers seated when it is full, equivalent to the seated passengers in about two buses, but this is not as bad as it seems:
    — Full load is not everyday load, and is often limited to things like a big event at the stadium.
    — FIT expects to see a vehicle running about every 5 or 7 minutes at peak hours, so the seated capacity is equivalent to about two buses every six minutes or so, a bus every three minutes.
    — The ride is much better than a bus, with no need to hold on.
    — A very common sight on light rail is passengers standing even when there are plenty of seats.

  16. John Rankin, 15. May 2019, 16:09

    @Helen: I just got back from Vancouver where I did a lot of travelling on their SkyTrain light rail network. The vehicles are similar in size to the proposed trackless trams and are also autonomous (no driver). The big differences are: fully segregated from traffic (in the sky and underground); and steel wheels on rails.

    Because they are autonomous and segregated, they can run at very high frequency and reliability: every 2-3 minutes all day and much of the night. What I noticed, in reference to your comment, is how smooth the ride is. As a result, many people choose to stand (a group of people stand chatting, which you can’t do so easily when sitting down). As Kerry says, I often saw empty seats even though lots of people were standing. The seats of choice are at the front; no driver and elevated tracks makes for great views.

    As an older person, it’s a practical impossibility to stand on either the SkyTrain or a Vancouver bus. A young person always insisted on letting me sit down. Vancouver also kept its trolley buses, including very cool express articulated trolleys. Helen, I think you would love it.

  17. greenwelly, 15. May 2019, 17:30

    @John Rankin, although the Skytrain system is not cheap. The most recent addition (the 19km Canada line that includes the airport spur) cost $2 billion Canadian (2009 dollars) – although this included significant tunnelling (done as cut and cover).

  18. John Rankin, 16. May 2019, 21:55

    @greenwelly: we need to consider whole of life costs and benefits, not just look at the capital cost of construction in isolation from the system as a whole. The game-changer is autonomous operation, which makes it really cheap to operate a high frequency service all the time, rather than just in the peak periods. All day, every day service has proved to be a powerful incentive for transit oriented development around SkyTrain stops. The value of such developments, and the economic activity generated, is a major shaper of Vancouver’s economic and social life.

    We know that fixed infrastructure like light rail gives the private sector the certainty it likes when making investment decisions. Since a claimed selling point for trackless trams is that you can easily change a route, can we have any confidence that transit oriented development will happen around trackless tram stops? At the moment, we have no evidence that trackless trams will match the city-shaping effects of light rail.