For some time, I’ve been meaning to write about German transportation systems like what’s an S-Bahn or what’s a Stadtbahn.

With the recent news out of Quebec, I figured I’d instead talk about a transportation concept that doesn’t actually transport anybody at all: the Gadgetbahn.

The word is a portemanteau of the English “Gadget” and the German word “bahn”, which means rail or train. A gadgetbahn is a speculative transportation concept that proposes to solve planning and financial issues via some sort of magical techno-fix, likely some technology that doesn’t even exist yet.

Classic examples of gadgetbahns are: monorails, “personal rapid transit”, maglevs, or the newest addition to the family, the “hyperloop”.

Proponents of these technologies may be referred to as gadgetbahn enthusiasts, or more derogatorily, “pod-people”. They often promise the sky in terms of reduced cost and increased speed and comfort, often with little consideration for capacity, risk, safety or realism.

Back to Quebec: the prime minister decided he wants a fast transit link between Montreal and Quebec City, but not a train, because “we can do much more modern things now”.

Instead, he wants something “futuristic”, something from the minds of Quebecers. (note from editor: Sorry to pop his bubble, but Quebec is not exactly known for having a long history on the bleeding edge of transit technology.)

The problem of the gadgetbahn isn’t necessarily that it’s a techno-fix. It’s that it is a technology for the sake of technology, a shiny gizmo to brag about, with little regard to solving the actual transportation problem.

The transportation minister clarified his position himself: he wants anything you can conceive of, any project; innovate, come up with new ideas!

And somehow, some consortium sprung up ready with proposals, renderings, promises and deadlines to build a high speed monorail (“MGV”), and all they want is a quarter of a billion dollars to develop it.

Cost, Speed, Comfort– The problem is geometry, physics and the Right of Way

The beauty of proposing a gadgetbahn is that since it doesn’t exist, proponents can make up all sorts of quasi-magical properties for their technology, which supposedly make it superior. Since there aren’t real-world examples, proponents can use the most optimistic theoretical scenarios they can come up with, and compare them with the actual performance of projects that have been built and which are bound to the constraints of the real world.

For example, the high speed monorail promoters claim their system is cheaper than conventional rail, because they could just use existing highway medians, with an elevated rail system where vehicles are suspended from above.

When you look at its basic structure, compared to conventional rail, this monorail essentially differs in the method of propulsion: instead of two wheels on two rails below the train, we have two wheels on one rail above the train.

Like for any gadgetbahn, the claim is that this new technology provides more speed, more comfort at lower cost.

But in the real world, these three aspects are always intricately connected and subject to tradeoffs – due to simple geometry and physics.

Want faster transportation? Then you need very straight tracks. Don’t have straight tracks but still want high speed? Then your trip will become a barf-ride, so less comfort. Want to build cheaply in an already existing highway median? Well the highway curves are made for cars going at 100km/h, so your choices are:

slow down (less speed),

run inside the existing geometry at higher speed (less comfort),

straighten the curves (more expensive).

These problems will always come together. At the end of the day, you’re still pushing a metal can full of people at high speeds you can’t get out of issues of geometry and physics by changing where you put the wheels.

Going further, once it appears the basic problems have been overcome, the next issues become capacity, safety, energy and access (stations).

For example, Elon Musk is proposing to build tunnels with his “Boring Company”, which will supposedly be cheap, because the tunnels will be relatively narrow. This reduces capacity, because only smaller vehicles will fit in the tunnel. To compensate, he may propose that vehicles will run super close together – which will represent a huge safety issue unless they run slowly. A small tunnel with a lot of vehicles that are barely smaller than the tunnel diameter, running at high speed may become a death trap in case of emergency, if there isn’t enough space and facilities for egress. If somehow he manages to solve all these issues, there’s still the problem of getting everybody into this tube of his.

All these considerations come down to the one fundamental constraint on which everything else depends: the right of way — how much space do you have available, how straight is your path, how and where is the downtown access, and how much space is available at stations.

The Maglev

An example of this issue is the maglev technology (essentially magnetically elevated monorails). The concept has been around for ages. The Germans and Japanese have been developing the technologies for a long time. In the early 2000s, the Germans were able to sell their Transrapid technology to China for the Shanghai Maglev airport connector, a 30-km line. It was a pilot project, with the hope to eventually cover the whole country with maglev network.

The Maglev was seen as the next generation of trains, mostly by being faster. But there was also the hope that it could even be cheaper, by putting the whole track on stilts, without having large elevated bridge-like structures. But in the end, conventional high speed rail and maglev require similar geometries, a similar kind of infrastructure, and it turns out that the speeds are not that different (Shanghai Maglev up to 430km/h, conventional rail up to 350km/h, both with a maximum experimental speed of around 600km/h).

At more than 300km/h, a lot of energy is spent to overcome the air drag of the trains themselves. Issues also become noise, and the required straightness of the infrastructure. And the issue that with stops, decreasing travel time by increasing maximum speeds becomes marginal. Overall, speeds above 300km/h tend to become uneconomical, no matter the propulsion system.

All of these issues come together to make the technological choice a bit of a wash.

In the end it makes more economic sense to build from conventional technology which has been developed for a longer time, has multiple vendors, has existing infrastructure that can be built on top of. This way, you can upgrade lines for high speed service, while being able to run the new high speed trains on existing tracks inside cities or to other cities. This provides a huge economic advantage.

So indeed, although the Shanghai Maglev works, in an economic sense it’s a failure. It convinced the Chinese to focus on high speed rail: ten years after the opening of the Maglev, the country still had the same 30km of maglev, but built 20,000km of high speed rail.

(Oh and btw, I’ve taken the maglev, it’s not a very smooth ride; it rumbles like a rollercoaster)

The Real Issue: Economics

The real issue of using a gadgetbahn to solve a transportation problem is not really technical. It’s that it re-frames the problem to build an infrastructure as the problem to develop a new technology — now you’ve got two problems to solve!

The technical problem should really be solved through private investment, not public funding. Thus I view the ‘offer’ to develop the “high speed mono-rail” for “only” 250M$ with a great amount of distrust. If the idea is viable and the people behind it are competent, it should have attracted private investment, as there should be a potential to make profit selling the technology. After all, the proposal has been around for 23 years.

When proposing a completely new technology in order to solve a specific transportation problem, the major problem is Risk:

Technological risks : Will it even work? Will it deliver on claims? Will it have sufficient capacity?

: Will it even work? Will it deliver on claims? Will it have sufficient capacity? Cost-related risks : How much will it cost to develop? How much will one kilometre cost once the technology developed?

: How much will it cost to develop? How much will one kilometre cost once the technology developed? Regulatory/safety risks : Will it be safe? What will safety requirements be? How fast will we be allowed to run?

: Will it be safe? What will safety requirements be? How fast will we be allowed to run? Risks because timelines are not understood : How long will it take to develop? How long will it take to plan & construct?

: How long will it take to develop? How long will it take to plan & construct? Operating Risks : How much will it cost to operate? How much will it cost to maintain the infrastructure? Will automated/unattended operation actually be possible?

: How much will it cost to operate? How much will it cost to maintain the infrastructure? Will automated/unattended operation actually be possible? Risks because we need to build complete systems at once , rather than incrementally updating existing infrastructure.

, rather than incrementally updating existing infrastructure. Also, new technology means relying on a single vendor, which is again extremely risky, both in terms of cost and availability of the technology in the future: Will the vendor exist in the future? How much will they charge us once we depend on them, given the lack of competition?

For any technology that’s already existed and been researched for decades, and that may have tens of thousands or hundreds of thousands of kilometers of infrastructure built today, all these question are much easier to answer. There will be much less risk, and thus less cost.

Be distrustful of Gadgetbahn Concepts

Any time somebody in power proposes to solve an infrastructure problem by first developing some new technology, or by using some proposed technology that hasn’t been delployed yet, we should be distrustful.

Often, the proposal may simply be an excuse to not invest in infrastructure today, because tomorrow some techno-fix will come along and solve all our problems ‘for free’. This tactic may work especially well if the proposal includes an appeal to some futuristic dream or a nationalistic project.

The gadgetbahn may really just be a big diversion. For example in Quebec, the most realistic scenario to get a fast link between Montreal and Quebec is the “high-frequency train” proposed by VIA rail, which would link the cities with conventional rail. After repeatedly proposing high speed rail for the last 40 years and getting no support from the governments, VIA decided to propose a system that’s not true high speed rail – but it would use dedicated passenger rail tracks, allowing somewhat faster speed than today, and no interference with freight.

This would hit an economic sweet spot for VIA, allowing them to almost finance and build the system themselves, with only relatively little public support.

But the main problem is the access to Montreal – VIA hoped to use the Mont-Royal rail tunnel to access Gare Centrale. But with the REM light rail project pushed hard by the prime minister, the tunnel would be converted to light rail, an incompatible technology, which will cut VIA off. In some sense, the prime minister’s announcement that he wants some gadgetbahn to Quebec City means VIAs rail project would become obsolete, and the conflict would become moot.

So is it really just a diversionary tactic to hide the regional rail planning problems in Montreal?

Interesting related reading (and with thanks for some inspirations) by Alon Levy:

“Loopy Ideas Are Fine, If You’re an Entrepreneur”