Why You Shouldn't Put Light Rail in Tunnels

hey everyone welcome back to rm transit today we are going to dive into a type of transit project that's seemingly appearing the world over trams or light rail which is heavily tunneled or put underground from auckland to toronto to seattle i'm going to make the case that the type of lines we're seeing often don't make sense and i'm going to explain why let's dive in [Music] if you're not already consider following me on instagram and twitter for all of the latest updates and make sure you're subscribed and you hit the bell icon down below so you get notifications when i release a new video before we can actually break down this somewhat new and concerning trend we have to talk about where trams make sense in the larger transit ecosystem in my opinion of course there are tramways which are lines which use space often around or in road right of ways sometimes elevated or underground but fairly rarely to provide a transit service that is usually local in its capacity and tram trains which are tram lines extended further outside of cities to make use of the ability to through run your vehicles tram trains tend to have a high level of priority over other traffic kind of like a regular train line with things like crossing gates and the like meaning that you have basically absolute priority even if there are road crossings and the like over your tracks now increasingly around the world the projects we see don't really fit these typologies instead these lines often act as a bit of a hybrid between a metro style of operation some bits of tram operation and sometimes some bits of tram train operation these types of hybrid approaches often come up when there's an obstacle in the way of having full grade separation or a fully metro style of operation or when a line is seen as not being able to attract enough ridership to demand full grade separation or when it's just seen as too difficult to separate transit from cars in auckland this looks like a new line which has recently received a fairly detailed proposal which calls for trams and tunnels for much of its length connecting the city's center with the airport and with fairly well separated space for the line even when it's not in a tunnel the project feels a little unclear in its purpose is it meant to be a metro serving the dense urban core a tramway serving as a local transportation option or an air rail link should a single transit line really try to operate as all three of these things now the more i read about auckland's proposal the more it starts to sound like seattle's link light rail and perhaps even more so like toronto's eglinton crosstown which has very similar technical specifications the concerning thing is that while the ship is kind of sailed for toronto and seattle we've already built our lines auckland still has time to change its mind and go with a different approach to building this type of transit well i've talked about how i feel the flexible nature of light rail means that the cost is that you don't do any one thing particularly well except perhaps operating as a tram i think this notion can really be extended to an entire transit line and this style of transit line in particular rather than making difficult decisions like committing to a full metro or deciding that you're not going to build one at all this line kind of sits on the fence and really doesn't do any one thing which might potentially mean that it has some of the benefits of all of these different approaches to transit but it also might mean it has all of the drawbacks and that might be worse than all of the benefits for example putting part of the line on street means that the trains are at the whim of drivers meaning you can't have the metro level of performance and independence from regular traffic at the same time by putting a large part of the line in tunnels you can't have the low costs of light rail and i'd argue that things are actually even worse in auckland's case because not only is this project aiming to be an aerial link a metro and more but there's also mention that the line is being designed such that it could eventually cross the water and serve communities on auckland's north shore via a tunnel to understand why this is a bad idea you need to understand that tunnels are tunnels at least mostly when it comes to electric transit there's no fundamental difference between a tunnel for a tram a tunnel for a subway and even a tunnel for mainline rail as long as the trains are of similar sizes which they often actually are a great way of illustrating this is looking at toronto the tunnels built for our most recent big subway extension are actually smaller than the tunnels being used for these small trains on our eglinton light rail line and they are indeed quite a bit smaller than the subway trains operating on the t-y-s-s-e and again the light rail specifications that auckland seems to be mentioning feel quite similar to toronto's once you realize that the modes don't make too much of a difference when it comes to utilization of tunnels you realize that if you're going to build a tunnel you might as well try to fill it up with the highest capacity mode you can and that's generally going to be a metro or other style of high floor train because it puts the equipment under the floor rather than within the cabin and on the roof freeing up a lot more space to carry passengers there is some general nuance to this though to maximize the capacity of a tunnel you want to use trains which are as long as possible since you can generally run a set number of trains per hour through a tunnel and longer trains means more capacity that said at the same time when you're considering the value you're getting for your money if you have to build stations on either side of your tunnel well longer trains are going to be in a much more expensive station so there's a sweet spot somewhere where you get the maximum capacity per dollar and that really depends on how many stations you want to build underground in auckland's case the additional money to take this tunnel light rail and that is a mouthful plan to light metro probably isn't that significant at worst it would probably improve capacity and line reliability but at best it might even reduce the cost of the project the reason for this as i've talked about in a ton of different videos is that light rail trains aren't necessarily optimally designed for capacity they're really designed for flexibility and often being able to operate on streets if you can have a train which is much shorter but is wider and can operate more frequently it can carry these same number of people but use smaller stations and since stations are one of the driving factors to the cost of a transit line having smaller stations can actually mean you save money even if the capacity is the same now if you're a regular viewer of the channel you might be asking quite reasonably what about stock bond systems in germany they do tunneled light rail why shouldn't we and i think this is actually such an important point and a really interesting one to discuss cities like karlsruhe and germany do build tunnels to bring their light rail networks through their city centers and so maybe there is a case i'd argue not so fast in these cases the tunnels built tend to be fairly short they're very strategic designed to remove a major congestion point or help with throughput through the very core of a city center tunnels are often only a few kilometers if that with only a couple of stations compared to cities like seattle and toronto who put a substantial portion of their lions underground with a number of underground stations at the same time many of these cities in europe benefit from having fairly large tram networks and so a number of routes can be through rooted into the tunnel that means better utilizing that tunnel capacity and having a lot more benefit on day one since you have an existing ridership base that already is using this transit network at the same time it seems like projects in north america as well as in new zealand are using deeper tunneling and tunnel boring machines which are making things more expensive than simple short cut and cover tunnels that you might have seen in places like germany basically my point is a small tunnel to maximize the value of an already popular tram network is very different than an entirely new transit line which is essentially a single transit line that simply uses tram vehicles and has a tunnel they're pretty distinct now if you must build a transit line with low floor trams you should probably build a tramway since that's what low floor trams are designed to do i know i often spend a lot of time talking about the rolling stock but i think it's so important because the rolling stock you choose is really the tool you're choosing to use for the job and the wrong tool can mean you're leaving ridership and benefits of your transit on the table now this is the part of the video where i give some free transit advice at least some thoughts that i have about auckland's approach for one if you're already willing to spend this much money for a light rail option you should seriously consider light metro i like to remind people that vancouver was actually smaller than auckland when it built its first skytrain line and so there's no reason that auckland might not have the transit demand for that level of transit in the future and if you're willing to spend the money you might as well get more bang for your buck it's also worth pointing out as i've talked about in previous videos probably linked up here there's a lot of cities in europe that are way smaller than auckland or vancouver that have light metro systems so i don't think city size is a huge issue here that said i do think it's worth questioning whether this technology and alignment is really the best approach and whether having a single project which tries to do so many different things is better than having several smaller projects for example connecting to the airport feels pretty reasonable and actually quite natural from the regional rail network and the regional rail linked to the airport is a pretty normal thing to see in europe or even across the water in australia not only are there two locations on the regional rail network which are fairly close to the airport one to the north and one to the east but both are not far away from pretty reasonable motor ray corridors where you could build some sort of elevated viaduct to take your trains straight into the airport itself not only would this probably provide a fairly fast and high quality form of transit but it would help better utilize existing investments in the regional rail network which i think is something to consider this style of connecting an existing regional rail corridor to an airport via an elevated rail link is something you see in places like toronto as well as brisbane now for serving the north shore my immediate inclination is using mainline rail because again you want to try to maximize the capacity through this tunnel and light rail probably isn't going to do that since you don't want to build gigantic light rail stations but the mainline trains in auckland are already moving towards a nine car standard an underwater tunnel does not come around every day in fact it might be a once in a century project and so you want to get the maximum capacity and value out of it designed right a rail tunnel could even be used for freight service during overnight or low frequency periods again designed right looking further into this and looking at auckland's rail network after city rail link something you might notice is that the network is unbalanced the number of train lines which naturally route into brittomart station from the west are different from the number traveling in from the east this lack of balance will mean you have a sub-optimal usage of the station and adjacent tunnels since you'll have to turn some trains around since there simply won't be symmetrical capacity going in both directions in this case what feels like a natural thing to do is to either take the eastern line or one of these services to the south and route it into a new tunnel which potentially adds some new underground platforms at brittlemart and then passes across the harbour and ideally gets up to surface level fairly quickly so that it can once again serve stations on the surface not costing too much money this is probably a more expensive approach to connecting with rail across the harbor but it is so much better than simply using light rail as this would be a mainline rail connection and it would provide the flexibility that that can offer it would also work with the city rail link to further disentangle auckland's rail network by reducing the amount of track sharing that we see and there's a couple different options that can make it quite compelling once the issues of connecting the airport and providing for a future cross harbor link are already dealt with i think the final issue is local transit within the dense core of auckland and i think that's where a tram or light rail system actually makes a lot of sense as you might be able to see i think that this larger transit project can pretty logically be broken into several smaller more focused ones i think my general attitude to all of the lines i've talked about today is that they often end up feeling like frankenstein's monsters combinations of several projects which might really be better off as separate projects or projects which really should be scoped up to full metro or scope down to just light rail recognizing the value in these different approaches to building transit is critical because we have so much more transit to build thanks for watching [Music] you

Channel: RMTransit

Views: 225,040

Keywords: transit, transportation, rail, railway, railfan, light rail, lrt, light rail transit, train, tram, tramway, tram train, stadtbahn, seattle, seattle link, eglinton crosstown, auckland, auckland light rail, urban planning, public transit, public transportation, public transport

Id: i-9sLvdqcJY

Length: 12min 26sec (746 seconds)

Published: Mon Feb 07 2022