An open letter on trackless trams

Councillor Roger Blakeley
Greater Wellington Regional Council
P O Box 11646
Wellington 6142

Light rail or trackless trams: issues to consider

Dear Roger

I write on behalf of FIT Wellington in response to your request for background information regarding the capabilities of autonomous trackless trams (a form of bus rapid transit). I understand these are being considered as an alternative to light rail. Here are some issues for you to consider.

More grass with light rail or more asphalt with trackless trams? © Romti / Adobe Stock

More grass with light rail or more asphalt with trackless trams? © Romti / Adobe Stock


To make a like-for-like comparison, FIT assumes the service will be designed for high-capacity rapid transit, regardless of the technology chosen. This includes two dedicated transit lanes on-street, signal priority or grade separation at intersections, low-floor vehicles, zero maintenance road bed with a 25+ year life, and relocating underground utilities to avoid service disruptions. Reliable on-street operation means there is a practical maximum 2½ or 3 minute service frequency.


How much capacity is needed over the life of the investment and can trackless trams meet the capacity? If the line opens in 2029 as LGWM proposes, the peak of the peak demand is about 5000 passengers per hour. Over the life of the system, FIT expects demand will double to 10,000 passengers per hour. On-street light rail can accommodate this demand with vehicles up to 63 metres long, with a capacity of 470 people. The claim is that a trackless tram can carry 300 people (500 on a longer model). Light rail vehicles of the same size have a quoted capacity of 230–250 people. This suggests 300 and 500 people are crush loadings, incompatible with reliable service and rider comfort.


Can trackless trams deliver the same quality of service as light rail? The claim that trackless trams can easily leave the track, and the reality that other traffic can drive on the track, means trackless trams cannot deliver the same reliability as light rail. Mixing with general traffic is incompatible with a rapid transit service. Wellington would need protected trackless tram lanes for the same reasons it needs protected cycle lanes. There is no data on trackless tram stop dwell times, but the claim that charging will take place at stops suggests longer dwell times than the 20 seconds typical of light rail. We’d also need end-of-line space for full recharging.


Is there a wide choice of qualified suppliers? Standards-based light rail vehicles are available off-the-shelf from a wide range of suppliers with a proven track record. Currently, autonomous trackless trams are available from one supplier only, are unproven commercially, and being based on proprietary technology would lock Wellington into a single supplier in perpetuity. The exit cost of replacing proprietary technology to escape this lock-in needs to be considered in the whole of life cost analysis.


How confident is GW that the technology is fit for purpose? Prudent system operators are generally neither the first buyer of new technology nor the last buyer of old technology. There is one demonstration line using 3-segment trackless trams. The 5-segment trackless trams Wellington would need currently exist only on paper. Fully autonomous on-street rapid transit is unproven technology, with no real-world implementations. The non-permanent nature of trackless trams means they are less likely to stimulate transit oriented development around stops. FIT’s view is that the least-risk approach is for Wellington to adopt the same rapid transit technology and standards as Auckland.


What is the whole of life cost? The often-quoted figure is that light rail is cheaper than bus rapid transit when the system carries more than 3500 passengers per hour. If the trackless tram is autonomous, this removes the biggest single operating cost, the driver, and changes the economics. Autonomous operation, whether trackless tram or light rail, makes the cost structure of rapid transit more attractive. However, autonomous on-street operation is currently at the pilot project stage, in vehicles which still require a driver. If the road bed is unsuitable, the maintenance costs from wheel damage will offset the cost saving claimed on track construction.

If trackless trams are chosen and prove unsuitable, what is the exit cost to upgrade the line to light rail and how would this be achieved in practice?

Yours sincerely

John Rankin, FIT Wellington