Auckland’s budding rapid transit network is already starting to make a significant difference to public transport in the region. Despite only being a few routes, now around 25% of all PT trips in the region are made on either rail or the busway, up from just 5% a decade ago – and the numbers continue to growth strongly with over 20% growth currently being seen. I’ll probably look at it in more detail in a separate post but I suspect in the future we could easily see that increase to over 50%, even improvements that are coming to local buses.
The overall goal of the RTN is to provide a strategic network of high capacity, high frequency routes which are largely free of congestion. Recent conversations about light rail and other topics got me thinking about the capacity of AT’s proposed RTN and in particular, just how much capacity do those plans allow for and is it enough?
For the foreseeable future, I think it’s safe to say that outside of the city centre the capacity of rapid transit is likely to easily exceed demand so for the purposes of this post I thought I would focus on just the level of capacity to the city centre.
Starting with the heavy rail network we will effectively have what we have now plus the CRL. The image below gives an indication as to the level of frequencies we could possibly see in the future – I think we will likely need higher all day frequencies but doing so wouldn’t affect the peak calculations I’m working at here.
At the peak this pattern gives us a total of 18 trains per hour in each direction so 36 all up. But just how much capacity is actually available would also depend on how we deal with Onehunga. For the purposes of this I’m going to assume that Onehunga trains remain only a single EMU so only three cars in length. I’m also going to assume that the three services an hour that turn around at Newmarket before heading back do so empty.
We know a 3-car train can comfortably carry around 375 people while a 6-car train can hold around 750 people. They could of course carry more by adjusting the seating to have more sideways and/or expecting people to cram in more but for now we’ll leave it at the current setup.
Based on the info above we have both the Eastern and Western lines able to deliver around 12 trains an hour while the Southern/Onehunga line delivers nine trains an hour. Accounting for the Onehunga line as mentioned this suggests the network could be able to deliver almost 24,000 people and hour (Britomart currently sees just over 10k during the two hour AM peak). That’s impressive and would be even higher if the Onehunga line could handle either longer trains and higher frequencies.
Light rail is perhaps the trickiest of the modes listed here, simply because we don’t have any of it yet installed to compare to so that means we need to go off what AT say. They suggest that light rail like being proposed for the isthmus and to the Airport could have a frequency of up to one vehicle carrying 450 people every 2.5 minutes. Given the map shows both Dominion Rd and Sandringham Rd LRT, I assume it means they could each be running with five minute services. Whether those volumes are over one route or two doesn’t make a difference for these calculations. Based on these figures suggests that light rail could carry nearly 11,000 an hour each direction at peak.
That’s obviously less than the rail network, but then again LRT could potentially only be one line while the rail network is three and a bit. With the individual heavy rail lines carrying possibly up to 12 services per hour and with up to 750 people on-board each service that one LRT line could have a slightly higher capacity.
The plan above still relies on a lot of buses to the North Shore and in future to the North West potentially clogging up our city streets – not to mention all the local buses from various non-RTN routes that will still be around. Recently AT and the bus operators have started rolling out double deckers many routes and by 2041 I expect they’ll be the main style bus in service. For the busways I’ll assume that they’ll be running with a frequency of one double decker every minute. That gives us a capacity of around 6,000 an hour per busway so all up another 12,000 people.
Of course if we did link up the planned Isthmus Light Rail to the shore this could increase capacity further.
So based on the figures above we get:
- Rail – 24,000
- Light Rail – 11,000
- Busways – 12,000
- Total – 47,000
So a total of around 47k per hour or 94k people during the two-hour morning peak and on top of that is a plethora of other bus services from places not directly served by the RTN such as the western North Shore and on the isthmus on routes such as Mt Eden Rd.
To put that in a little perspective. As of last year there were about 105,000 people working in the city centre and on top of that there are also 10’s of thousands of students. Of course across both employment and education, not everyone is going to be turning up each day. The last figures I saw suggested around 80,000 people enter the CBD in the two hour AM peak of which around 50% do so on PT. With the RTN routes alone being able to deliver more people to the city than currently arrive by all modes, that represents a significant increase on what we have.