Monorail Construction Costs
Supporters of monorail and other sleek structures argue that because the structures are thinner than conventional rail viaducts, they’re cheaper and more aesthetic. They even argue that viaducts, which are more expensive than at-grade construction, are actually better. Transrapid does that, and Hyperloop does that as well. Hyperloop proponents specifically mention the the structure’s lighter weight as an explanation for the lower proposed cost – see my post update and the comments for extensive discussion and explanation for why the proposed Hyperloop costs are still an order of magnitude too low to be realistic.
Not having reliable construction costs for the intercity modes, I went and looked for construction costs of urban monorails, which are usually put above-ground, where their sleekness is a major advantage over conventional rail since they do not darken the street as much.
The resource with the most information is a JRTR article about Japanese intermediate-capacity rail, including both monorail and significantly less sleek automated guideway transit (AGT). It includes a diagram of monorail structures, which can be seen to be quite light and thin. The width of the structure from guideway to guideway is 4.5 meters including both guideway widths, and including the outside appears to raise it to 5.5. Two-track elevated conventional rail structures typically range from 7 to 10.5 meters wide.
The most recent Japanese monorail on the list, the Tama Monorail in suburban Tokyo, opened 1998, was $2.422 billion for 16 km: $151 million per km.
The one Japanese project more recent than the JRTR article, the Okinawa Monorail, built from 1996 to 2003, was $1.1 billion for 13 km: $85 million per km. The cost cited on the Monorail Society’s webpage is less than a third that amount. An extension to begin construction soon is projected at $350 million for 4 km, about the same cost per km.
Other Tokyo projects are not cheaper than the Tama Monorail. The AGT Yurikamome, opened 1995, cost $140 million per km as per JRTR; the Tohoku Jukan Line, a conventional elevated structure on top of an older elevated structure located in Central Tokyo, is $400 million for 1.3 km of new el and 2.5 additional km of new track on existing structure, which is $300 million per km if one considers the cost of everything except the new el to be zero, and about $150 million per km if the 2.5 km of existing structure is deemed to cost as much as at-grade rail, which is about half as much as an el typically. The ratio of elevated to underground cost is 2-3 and this is also in line with $150 million per km of baseline cost.
Outside Japan, we have the following projects, with their costs:
Chongqing Rail Transit Line 3: the first phase, built from 2007 to 2011, is ¥13.8 billion for 39 km, or in PPP dollars $88 million per km. About a third of the line is underground. An extension opened in 2013 cost ¥5.7 billion for 16.5 km (Chin.), or $85 million per km, all elevated. This is in a country where fully underground subways average about $150 million per km; but I cannot find cost figures for other lines in Chongqing itself, and any help would be appreciated.
Moscow Monorail: according to Wikipedia, 6.33 billion rubles in 2001-4, or $514 million in 2010 PPP dollars, for 4.7 km. This is $109 million per km, all elevated.
AirTrain Newark: the airport-internal people mover opened in 1996 and cost $354 million for 3 km, while the extension to the mainline train station was built from 1997 to 2000, added another 1.8 km to the project, and cost $415 million; both numbers are taken from the New York Times. Deflating both numbers to 1998, this is $1.03 billion for 4.8 km, or $215 million per km. In contrast, AirTrain JFK, a SkyTrain-like system, was $1.9 billion for 13 km and was built from 1998 to 2002, which in 2010 dollars is $185 million per km, actually lower than the cost of the monorail. Note that the AirTrain construction cost was not that high by normal-world standards: the same technology in Vancouver, in all-elevated configuration, is projected at C$116-150 million per km into Surrey when all elevated (see RRT alternatives 1 and 3 with distances of 15.5 km for 1 and 6 km for 3 as measured on a map), which is about US$95-120 million after PPP conversion. This is a 50-100% premium for New York over Vancouver prices, compared with a 400-600% premium for subway construction.
Palm Jumeirah Monorail, Dubai: Dh4.1 billion for 5.45 km, built 2006-8, about $1 billion in 2010 PPP dollars. This is $183 million per km, all elevated. Compare with the 17% underground Dubai Metro, mentioned in my previous post, which costs half as much per km.
Mumbai Monorail: the master plan is to spend 20,000 crore on 135 km, which after PPP conversion is $66 million per km. The under-construction first line is 3,000 crore for 19.54 km, or $69 million per km, all elevated. This compares with a parallel Mumbai Metro plan to build 146 km for 36,000 crore, or $111 million per km, of which according to Wikipedia 32 km, or 22%, is to be underground. This by itself suggests no monorail cost saving. But the first Mumbai Metro line is already over budget, at 3,800 crore, which again using Wikipedia for length (11.07 km) gives $154 million per km, all elevated. This suggests that in Mumbai there is a cost saving from using monorail, assuming all numbers are correct and that the Monorail Line 1 cost is not just the first phase, which is only 8 km.
I wish Keep Houston Houston was still around to comment, considering the post on “unconventional transit”.
Question: do these numbers include maintenance facilities? A big expense that will be incurred by the first segment of a system but not by subsequent segments.
I have no idea. I’m using headline numbers, which may even include vehicles. To a first-order approximation the numbers are comparable, though.
The question I had in mind was whether that were system prices.
Concerning maintenance facilities, due to the nature of monorails to be mainly single lines, chances for subsequent segments, in order to build a network, are rather low.
Meh, I’ll write something more about monorails somewhere at some point under some moniker.
But basically, monorail is a solution for when you already need grade separation.
If you can stick LRT in a median, that’s going to be cheaper than monorail. It’s only going to run 25-35mph, and it’s going to run over pedestrians every now and then, but these are tradeoffs we make for cost and LRT is still safer than buses (usually).
Likewise, in any sort of greenfield development where you can reserve real estate for at-grade heavy rail, that’s going to beat monorail on cost while equaling its safety and travel time. This includes underutilized freight rail ROWs (e.g. WMATA), expressway medians (e.g. Toronto/Chicago), and master-planned cities conjured from the desert as a sort of dick-measuring contest among various oil sheiks.
But if you’re right-of-way constrained – and a whole lot of lines are – monorail may win. That is, if your planners don’t throw it out at the beginning out of some combination of conservatism, “seriousness,” and keeping up with the Jones’s.
they do not darken the street as much.
So the monorail enthusiasts say. They may have been back in the 60s when the monorail was carrying a souped-up bus. Not so much in the 21st Century when they are the same size and length as multi-car trolley/tram trains and have elaborate escape walkways dangling off them.
I havent seen it in person, but pictures of the Sao Paulo construction show a much less intrusive structure than standard elevated rail
São Paulo’s monorail is very tall when compared to other elevated systems. From what I remember of last time I’ve been to São Paulo (last year), the line does not look so intrusive as I feared; but I would not know about how stations look when planted that high, because they were not there yet.
I dunno about the rest of you but that looks like two rails on a continuous slab to me.
So it’s a low capacity trolley car on a slab? The only Els I’ve seen are in New York City, Chicago and the East Bay. Those trains carry much more than a trolley car’s worth. And they have at least two …. guideways. More than two in some places in New York and Chicago.
I actually don’t generally find the elevated portions of Vancouver’s Skytrain (light metro-not monorail) to be an astetic problem because it is mainly in its own right of way away from other structures…..(there are some areas between New West and Edmons that it looks worse). I guess I should also comment on the articles main premise that the Hyper-loop costs for elevated structures is out to lunch…..clearly, good work Alon.
This picture is not of São Paulo’s monorail, but rather of Porto Alegre’s Aeromovel system I mentioned below. The concrete slab serves both as support for the rails and duct through which the air is pushed onto sails bolted underneath the vehicle. Apart from the propulsion method, it’s closer technologically to conventional rail than to monorail; for instance, as you can glance in this picture, switches/points might be built using similar technology, as opposed to the unsightly beasts needed to switch monorail tracks.
This implementation is a just a short shuttle (880m) between airport terminal and commuter train station, and yes, it consists of a small-ish cabin (up to 150 people) running back and forth on a single track on 5-10 minutes cycles. There is a larger vehicle (300 people) being built for this system, to be delivered next month. Another project somewhere in Brazil talks about getting even larger vehicles (600 people), but so far it is just a project.
Anyway, I mentioned it not because of the monorail subject (for it’s not one), but rather because of the thin-ish elevated structure its built upon, and it could be interesting to bring into the discussion for its novelty.
 http://portoimagem.files.wordpress.com/2013/04/20130413_115049.jpg (the switch has not been built at this time, thou)
It doesn’t look particularly thin to me. About the same size as a conventional El would be if it was single tracked. Meh., It’s made out of concrete instead of bare steel. Meh.
Well, while I agree that aeromovel is almost as thick as the L, one should note that it beats both El and Monorail in terms of emergency egress: no third rail hazard and reasonably large walkway. Also, the absence of engines onboard greatly reduces not only the weight and maintenance costs, but also the risks of fire-related accidents.
This picture looks like an automatic people mover to me, as you find in quite a few airports all over the world. I am not even sure whether it is actually a photograph, or whether it is an artists rendering.
I can assure you it’s a picture, because I took it myself 😉
And yes, it’s can be categorized as an automatic people mover. The only difference is that it does not carry an engine on itself, reducing dead weight.
No offense intended, fmobus… Actually, the system should work reasonably well, even over several kilometers; Isambard Kingdom Brunel proved that with the “atmospheric railway” between Exeter and Newton Abbot on the Great Western Railway. The main problem there was the sealing of the air pipe, but nowadays, better materials should be available.
None taken Max 🙂
Regarding sealing: I am told that new materials made things much better.
The escape walkways seen in Vegas/Newark are a consequence of small monorail cars with no means of egress under the side doors.
Standard bogies-under-the-floor Japanese construction allows fully vestibuled trains and emergency gangplanks the extend from the cabs. A second rescue train butts up against the first and voila, full evacuation. At least one diesel rescue vehicle exists in event of a total power failure (Godzilla, etc).
That should read: *no means of egress other than the side doors*
while the passengers are waiting for the diesel thingy to come, do they die of asphyxiation or incineration? You aren’t going to build high capacity transit without emergency egress, not in 2013
What emergency egress?
Or, if Chinese examples are too tacky, then what emergency egress (Japan version)?
I dunno why they don’t have egress. I’m putting my money on asphyxiation or trauma as the leaping passenger hit the pavement. And it doesn’t look all that much different to me than this
It’s thinner since the train partially dangles.
It doesn’t look all that much different to me. It’s concrete instead of steel. Whoopee!
Wander the Popular Science or Popular Mechanics archives. Monorail nirvana has been just around the corner for decades. Just like maglev utopia has been just a few years away for decades.
The side emergency walkways are mandated by law for new construction in the US, regardless of what’s allowed in Japan or China.
This eliminates the “advantages” of a “narrower” monorail beam.
Do the walkways have to be concrete? Maybe they can be thin steel mesh, just enough to support a human being. Maybe there can be just one walkway, located between the beams.
of course can be thin steel mesh
see wuhu city monorail in China
I would add São Paulo’s monorail as well. Its total cost was R$ 3 billion for 17km, which comes out as R$ 170 million/km. Not sure of the ppp conversion for those values, but it’s a price comparable to some subway projects elsewhere in Brazil.
On a slightly related note, an air-propelled system called Aeromovel is making its debut in Porto Alegre, a city in southern Brazil. Although it’s technically not a monorail, it works on thin elevated structures too. A shuttle line connecting the airport to a commuter rail was opened just this month.
Thanks, I was looking for Sao Paulo monorail cost figures but couldn’t find any.
Some of the arguments for monorails compared to elevated heavy rail is that they are less visually intrusive, capable to handle tighter curves with tilting and able to negotiate grades up to 7%.
Are monorails actually capable of tighter curves with tilting? Regular els can have a fair amount of superelevation – SkyTrain has it on the Expo Line, and even the Chicago L has some. I’ll buy that suspended monorails can do it better because their natural carbody suspension is in the correct direction, but can straddle-type monorails also turn tighter curves?
The lowered visual impact is a major benefit of monorails, of course.
Alon, the figures I found for monorails (I assume the straddle type) is a minimum curve radius of 50m~120m. I believe the Tama Monorail in western Tokyo has 60m radius curves in some spots. These are traversed at low speeds.
This MLIT document has figures on p. 3. From the left- subways, LRT, guideway transit, and monorail:
Click to access toshin2_shiryo5.pdf
Interesting that the minimum curve radius for a subway is quoted as 160 meters. The minimum radii on legacy subways are much less than that – 40 in Paris and New York, 60 in London – but those are all on lines that were built explicitly as separate from mainline rail, with smaller-diameter tubes than required to carry full-width mainline trains. Presumably the much higher standard in Japan comes from the fact that many (most?) subways are compatible with mainline rail and have through-service with commuter trains?
It could be that the reason is the loading gauge (in other words, the width) and the length of the carbodies; the very tight curves in the cities you mention are on lines with short carbodies, together with relatively big distances between the cars.
Yes, it could be that the current standard for length of new metro/commuter rolling stock in Japan is 20m. In the past cars were shorter- 18m, 16m in some cases.
With rubber tyres on concrete, you can safely do 11% grades (for example the new metro line in Lausanne which replaces a cog railway line). That means such grades are also possible with (Alweg type) monorails.
Linear induction can also achieve higher grades than standard traction.
Indeed. And these arguments are all nonsense in the US.
(1) “less visually intrusive” — maybe in countries which don’t require emergency walkways. The US does require emergency walkways for new construction. So, same amount of “visual intrusiveness”.
(2) “capable to handle tighter curves with tilting” — no, conventional rail can handle tighter curves than monorail. This is basic physics actually… conventional rail has passive stabilization, monorail doesn’t
(3) “able to negotiate grades up to 7%” — conventional rail can handle 15% curves, as the streetcars in Pittsburgh used to
Aaarggh — “15% grades”
In many ways this argument seems an echo of the standard gauge – narrow gauge argument of the last century . . .
The argument for narrow gauge trains was that they would be cheaper, lower-profile, etc. Which they were. There proponents had a similar zeal to some monorail enthusiasts. In Colorado and Switzerland the advantages were enough to prompt a significant system, but elsewhere the network benefits of standard gauge trumped all else, leaving narrow gauge branches isolated.
Hmmm… but then, what about the Japanese main network, or South Africa?
OK, in both places, the loading gauge is comparable to the UIC loading gauge for European standard gauge.
Max, what about them? You might as well ask why North American mainline trains with their extra-UIC loading gauges don’t use a larger (more appropriate) Russian 1520mm track gauge.
The original 1067mm (3foot-6inch, “pioneer”, “colonial” ) gauge was chosen for lower construction cost reasons (or because narrow gauge in the colonies was “traditional”, or because of export cartel agreements.)
In some parts of the world, the tiny loading loading gauge (and sharp curvatures, and light-weight track, and poor track alignment, and light axle limits, etc) was progressively overcome, while retaining the tiny track gauge for compatibility reasons. Non-optimal, but that’s the real world for you.
I’m sure if history could be done over everybody would have preferred standard gauge … and for that matter a wider “standard” gauge itself seems like a good idea ignoring all history, and it’s certain UIC gabarit partout should be much larger,, etc.
The previous message kind of associated narrow gauge with small loading gauge and low capacity. That’s the reason for the question. South Africa is with 1067 mm gauge in the heavy haul club, and when you look at the performance the Tokyo suburban/metro system produces, it is definitely not so…
But I agree with you that in most cases, lower construction cost, mainly for the roadbed and civil engineering work, was the key… a development which led to the 760 mm “Balkan” gauge, or the several 800 mm gauge mountain (cog) railways in Switzerland.
About wider gauge, per se, Isambard Kingdom Brunel was definitely right with the wider gauge for the Great Western Railway; those few centimeters more space between the wheelsets allowed for a better firebox and combustion.
Interesting, in German, the 1067 mm gauge is called “Kapspur” (Cape gauge)…
One thing I notice in debates in North America regarding different modes is the competitive attitude of “winner take all” held by many advocates- so if monorail “wins”, then other forms must be diminished. Same if another mode “prevails”. I think a better approach is to identify the needs and parameters, and apply the most cost-effective solution, be it subway, fixed guideway, or monorail. This is what is done in Japan- for example, when ROW is too restricted and/or tunneling too expensive, but high passenger throughput is required- monorail is a viable solution.
Andrew, the reason that debate in the USA seem to be “winner take all:” is because it really is winner take all.
Particular projects — meaning very specific choices of consultants and vendors, fronted by very specific “public” agencies; not meaning solutions to public policy problems — are in competition to deliver the maximum dollar amount of earmark funding, and the first step is to ruthlessly eliminate any cost-effective alternative and to ruthlessly defund smaller projects that might compete for the same earmarks.
The competitors for funding aren’t different technical “solutions” in a transportation corridor, they are different corporations withing the transit-industrial complex. (This is the exactly the same as with US military procurement.) So of course there is no consideration of cost-effectiveness and no identification of “needs and parameters”, because none of those are in any way relevant to the goal of locking in particular and vendors at maximum cost.
Killing off alternatives, killing off competing projects, and delivering winner-take-all public-private wealth transfers is precisely how the system is designed to work, and it works very well. You’re making a fundamental category error by seeing any of this as a technical-economic matter of mode choice.
Compatibility has inherent value. The “identify the needs and parameters, and apply the most cost-effective solution” approach is what gave us multiple incompatible rail gauges, multiple incompatible loading gauges, multiple incompatible electrification standards, multiple incompatible platform height standards, etc. This is causing headaches OVER A HUNDRED YEARS LATER.
So I say no! Pick one standard. That standard WINS. All projects should use the *standard* for their continent, even if that standard is not ideal in some sense.
Everything east of the Rockies, for mainline trains anyway, is going to be nominally 10 feet 6 inches wide, 85 feet long, use platforms that are 48 inches high and be wired up for 25kV/60Hz except in some places where the clearances are too low where it will get 12.5 kV/60Hz. Nothing awful about BMT/IND standards for subway though there will always be IRT sized cars being made… for what was the IRT, PATH and the Chicago El. Trolley cars are going to use standard gauge, for any new build, and use DC somewhere around 700 volts.
That would be sensible, wouldn’t it.
We still have 12Hz electrification from New York to DC, nearly-unique-in-the-world underrunning third rail north of New York, “trolley gauge” tracks in Philadelphia and Toronto, low platforms in Toronto and the rest of Ontario, linear induction motors on JFK Airtrain (that one’s relatively harmless), and more signalling systems than I can count.
And people are suggesting creating more incompatibility by building monorails. Seriously!
But but but monorails and maglev are going to be revolutionizing ground transportation in just a few years… since at least the 50s in the case of monorails and the 60s in the case of maglev. Just like the supersonic airplanes are were going to be whisking us cross country in a couple of hours as soon as they got rid of those pesky sonic booms.
At least from eyeballing other parts of the tracks and from making some guesses about catenary height in the tunnels, there’s enough clearance for 25 kV in the tunnels under the East and Hudson Rivers. The places with the really low clearances, like possibly the Park Avenue tunnel, are likely to just stay third rail.
They had to chisel out extra room in the Hudson Tunnels and the Baltimore and Potomac Tunnels to put catenary in. There might not be enough clearance for 25kV. There are other places where it might be a problem. The scuttlebutt on the Metro North boards is that Metro North selected 12.5 kV because going to 25kV wouldn’t have done much for them and there would have been a lot of work to get the clearance on a lot of bridges/overpasses. The alternate scuttlebutt is that Amtrak was specifying 12.5 kV but then changed their mind for the new wiring to Boston to be 25kV instead. A bit more expensive to implement, a bit more expensive to maintain but probably cheaper than building new tunnels under the Hudson. Once the trains capable of using 12.5kV approaching Manhattan it’s not especially expensive to do the same in a few other places. The scuttlebutt about the Park Avenue tunnels and Grand Central is that the 600 volt catenary that used to be in place was about as high as the voltage could go and still fit in a pantograph.
Switching between 12.5 kV and 25kV can be as simple as that, just switching. Would probably be computer controlled relays today but it could be implemented with mechanical logic. Or just a multi-pole switch.
Using conductor rails (as intruduced by Furrer & Frey), you can gain a good 10 to 15 centimeters in height in a tunnel with 25 kV voltage. I don’t know whether that would be enough in those tunnels, but it would definitely reduce the amount of lowering the tracks.
Voltage switching is normally really easy to design (although apparently some models of trains can’t handle it). *Frequency* switching is *not nearly* as easy, and requires quite a bit of extra equipment on the train.
Alon, can you do an article/post on SkyTran that is almost under construction in Tel Aviv:
It is not almost under construction in Tel Aviv. Tel Aviv being Tel Aviv, nothing is “almost under construction” – either it’s already under construction or it’s unlikely to start this decade.
I will take that as a “nyet”?
It would have been good to read your view on the actual technology. ie, can pylons be built so cheaply and be erected as quickly as they claim.
I am planning on building some type of rail system that will basically be a loop of about 30 miles. It will probably have about 60 stops and designed to carry heavy traffic. I was just trying to see which was the best way to go. I dont want to spend over $2 billion. All of the land in flat . Can anyone give me more info?
I’ve seen in other sites that the cost of the the Dubai Monorail was $380 million. You mention $1 billion!
Now I doubt all your figures…
Here’s a reference to the $1 billion figure: http://www.khaleejtimes.com/article/20090507/ARTICLE/305079948/1002
Thak you for your propmt reply.
According to Systra, who acted as Independent Checking Engineer, the initial budget was $380 million:
Click to access metro_dubaipalmjumeirah_en.pdf
The Dh 4.1billion looks like a typo on the budget in dirhams ($380million=Dh1.4 billion).
I’d like to point out the Monobeam system from Futrex, in both its initial version of smaller cars as well the larger version that’s more like a rail replacement.
V1: Smaller cars, tight radii, reduces speed.
While neither of these systems were ever deployed – for reasons unknown to me. I believe there’s something special there.
A quick summary (with some of my notes included):
Extremely arrow guideway beam: Is nothing like the eyesores of other monorail or elevated rail lines, and in theory can be customized to fit into the neighborhood aesthetic.
Dual direction on a single guideway. No need to double down on construction and maintenance costs, so its 2 miles for the price of one.
Branching: full branching enables a network to develop over time.
Grade separation: As with any grade separated rail or busway, is not dependent on street traffic conditions.
Modular: Should be “relatively” quick and easy to erect and modify.
Cost: Is relatively cheap. A price comparison can be found here: https://web.archive.org/web/20140504094252/http://www.futrexinc.com:80/Cost.htm
Maintenance facility: Due to the branching capabilities, lines can easily share yards if designed as a network.
Lack of egress: The existing development does not have an emergency egress model, which would necessitate further development.
Aerial path obstruction: Would need to deal with trees and other overhead conditions.
Terminus: There in an absence of information on terminal services, such as turnaround.
Overall: I see the smaller scale version as a serious contender for routes being explored for BRT, Tramway, and LRT. Imagine this as the BQX…
You’re citing a company site for the construction costs.
I have to, as there are no real world examples, and no real cost studies aside for maybe the Manila project that got far enough before it fell apart. However, I’m sure they would be happy to provide data to back the numbers up.
But frankly its the system and the way it can fit into and even complement the neighborhood that drew me to it, Especially when I see the problems with BRT lines in my hometown of Brooklyn.
Okay, so there’s no evidence to back up their low cost claims, and meanwhile there’s strong evidence that costs are insensitive to how sleek the structure is. (Also, their idea of a single-track monorail is really stupid.)
On the cost front, the lack of third party referencing puts a question mark on the estimates, although like I said I’m sure they had some stuff from when they were going out to bid on projects that they might be willing to share.
Why do you think the single track concept is stupid?
Because if you run trains frequently you can’t do that, unless the single-track segment is very short.
I assume you’re referring to segment blockage causing a line backup? that would be a problem with proper rail lines as well is single-tracked, but building these – if the price is right – allows you to still use buses as an emergency backup.
The big issue IMHO of any elevated structure is community acceptance, so anything else is not really an option. for city streets.
Buses in mixed traffic are not a substitute for your grade-separated system. Come on. And the issue isn’t the occasional backup, it’s that you can’t run a long single-track segment at any frequency; forget about even 10-minute headways.
To act as a temporary bypass between 2 stations in the event of a breakdown, I don’t think its the end of the world – especially with good street level traffic coordination. And in a sense its actually pretty similar to the old one-way trolley on tracks that pre-dated buses in cities like Brooklyn..
I totally get the the wish to put in best practices and all that. But at the end of the day having something is better than having nothing, which is why a low-profile system like this (not necessarily exactly this) “can” get past the general objections to elevated structures.
That said if further development modifications allowed for track switching all the better, and if WordPress comments allowed for editing I would put it into the “Cons” list.
Okay, but nowadays they only ever do one-way trolleys on streets that are too narrow for two tracks.
True! But I was thinking of this as a bus and BRT alternative as a compliment to rail, not as a replacement for proper rail when suitable. One thing I’m sure of; if you replaced buses with a grade separated system of any sort, the ridership would rise dramatically.
What you’re missing is that the Futrex (and Project21) cars hang off the sides of the single beam. A single beam is double-track, thus the name (Project/System 21: 2 tracks/lanes, 1 beam).
I would say grade separation supersedes redundancy needs.
Do you know any figures re. the cost of suspension railways? The designer of one in China estimates that it would be at least 5x less expensive than a comparable subway (https://www.railwaygazette.com/news/single-view/view/sky-train-on-test-in-chengdu.html), which seems a remarkably low figure. I’ve seen a figure for the Shweeb cycle monorail PRT… thing of only $2.5 million per kilometre – replace the personal cycle pods with electrical cabins and you’d have something that could work as transit.
The maximum speed I’ve read of with a suspension monorail was 160 kmph, achieved using propellers. Now if monorails could be built along/above motorways and achieve such speeds… remember to wave to the slow people down below stuck in congestion as you go by.
The Daily Mail reports that the cost for the Skytrain is $16 million – https://www.dailymail.co.uk/travel/travel_news/article-3817276/Suspended-service-China-unveils-elevated-monorail-carriages-HUNG-tracks-like-rollercoaster.html – but it doesn’t give the length of the system. Assuming they’re talking about the 1.25km test track, that would be ~£13 million/km, which would accord with the cost comparison to subway constructions.
I don’t know why people would take an issue with having a monorail above their streets. They seem perfectly happy to have cars turn their streets into traffic sewers.
There are very few examples of this. The most recent one in Japan, in Chiba, cost about what I’d expect of an urban el (link).