Ever since it was announced light-rail was being considered to rail to the airport there has been a ton of debate about the merits of it compared to extending our existing rail system. This has only increased in the last week since we launched the Congestion Free Network 2 (CFN). Last week I looked at why we can’t just throw more trains down the CRL, meaning an additional corridor through the city is needed. Today I’m looking at another frequent point of contention, does light-rail have enough capacity.

I think one issue is many people believe light-rail is just modern versions of dinky trams pootling down roads shared with traffic. But light-rail asproposed by Auckland Transport and expanded on by our CFN would have some serious people moving grunt.

So, here are some examples showing what is possible overseas and often it’s not about how heavy your rail is but how you use it.

Seattle

We’ve talked about Seattle’s Light-Rail before, largely because it is it has so much in common to what is proposed in Auckland. The single, 32.8km long, 16 station line is largely grade separated system but includes a 7km on-street section that is separated from the general traffic lanes by a concrete kerb. It takes their light-rail vehicles just 48 minutes to traverse the line so about the same speed as and length as from Papakura to Britomart.

The important aspect for this post though is the capacity. Using 29m long vehicles, each one is capable of carrying around 200 people. However, multiple vehicles can be coupled together to increase capacity. Two and three unit trains common with the system designed to allow for up to four trains to be joined. Services run every 6 minutes during the peak and 10 minutes off-peak – less frequent than we propose for each of our light-rail lines.

So how does it perform? Well, as of February, this single light-rail line carries more people each year than Auckland’s entire existing rail network. Ridership has grown amazingly rapidly following a couple of extensions to the system last year.

Dallas

The Dallas system isn’t one we’ve talked about before but relevant in this discussion. The light-rail network there consists of four lines on a largely separated corridors out to the suburbs however they all combine through the city centre on a single dedicated street level corridor. Each line operates with a 15-minute frequency resulting in one through the city centre corridor every 3½-4 minutes. The vehicles are also capable of up to 110km/h which is the same as our current electric trains.

The system uses 37m long vehicles (above) capable of carrying about 200 people. Like Seattle, it’s possible to couple couple up to four vehicles together for a single train, although two to three are more common. This length is an element I’ll touch on later in the post. The system carries 30 million trips a year so despite being at street level through the city centre.

Vancouver – Canada Line

Vancouver’s Skytrain network might not be street level light-rail like we’re talking about here but is useful for discussing capacity. The system uses 41m vehicles capable of carrying 300-400 people each. Unlike the systems above, are not coupled together, relying on high frequencies to move up to 15,000 people an hour in each direction. This is of course made easier and cheaper by the system being fully automated. The numbers are impressive with almost 44 million trips made in the year to the end of February.

Light-Rail and the CFN 2

The point of all of this is that the light-rail proposed in the CFN 2 is light in name only. Each of the two lines would be capable of carrying more people every day than our entire rail network does right now.

What’s more it would be possible to get even more capacity out of such a system. Auckland Transport have proposed using up to two-unit, 66m sets capable of carrying about 450 people each. Given the systems above and elsewhere, perhaps the system should be designed to allow for three coupled units. That would further increase capacity and shift the light-rail network close to what the CRL is capable of. Given it’s also many light-rail systems are capable of over 100km/h these light rail vehicles wouldn’t be slow either.

By way of comparison, light-rail with 99m vehicles could have the capacity to deliver up to 32,000 people an hour. That’s not too far off the ultimate capacity of the CRL, capable of delivering up to 36,000 people to the city centre. The proposed light-rail network would have more in common with our rail network than it does with old trams.

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