The Hungerburgbahn (Part 3)

A Hybrid Funicular, Image by Steven Dale

This is Part 3 of a 3 Part series on the Innsbruck Hungerburgbahn. Part 1 can be found here and Part 2 can be found here.

The Hungerburgbahn is what is known in the industry as a Hybrid Funicular. It is a unique and rather new technology that defies categorization and is bound to confuse. Even the simple act of calling it a “Funicular” is mistaken because it is only a Funicular in the strictest sense of the term for a disproportionately short part of its journey.

Hybrids are more mutt than purebred and that’s what makes them so special; they’ve got a good mix of genes from a large pool of possibilities. Hybrids are literally cross-breeds between three cable families: Cable Cars, Funiculars and Gondolas. It’s this cross-breeding that allows Hybrids to do things no other traditional or cable transit technology can.

Consider the Hungerburgbahn’s route: A vehicle begins in an Open Air Yet Underground (OAYU) station in downtown Innsbruck. The vehicle then journeys through a single tunnel and then darts quickly up to street level. It then gently ascends to a slim-profile station a couple metres above street level. After allowing riders to board and alight, the vehicle banks sharply to the left and crosses a river on an elegant single-purpose bridge. It then plunges below ground, tunneling under a major highway and then pitches back above ground where it starts a dramatic climb up the side of a mountain. It comes to a rest at its third stop in an inclined position at a dramatic station dangling at the edge of a cliff. The vehicle then finishes its climb and comes to a rest at its final destination in a second OAYU station.

A yellow hybrid vehicle makes the trek up hill (look closely in the upper left corner) while a blue hybrid vehicle departs the Löwenhaus Station and ducks underground. Image by Steven Dale

Now here’s the kicker: Despite the myriad of changes in inclination the vehicle goes through, the rider is absolutely unaware of anything. The inclination of the rider never changes, only the vehicle.

To imagine how Hybrids work, picture a car’s chassis, now imagine the same thing but in the shape of a streetcar. Now populate that chassis with 5 separate gondola cabins that are bolted to the inside of the chassis. These gondola cabins are not stationary, however; they are allowed to tilt freely and independently of the chassis which occurs naturally according to gravity. In all but the flattest tracks, therefore, a Hybrid’s chassis will be inclined to a different degree than the passenger compartments attached to the chassis itself.

A yellow hybrid vehicle waits at the Alpenzoo Station. Notice how the individual cabs are inclined separate from the grey chassis. Image by Steven Dale

It sounds complicated, but it isn’t. Much like a carpenter’s plumb-bob, a gondola will always find a natural, level inclination because it’s supported from above. It doesn’t matter if the carpenter is leaning forward or backward, the bob he’s holding will always find the same natural inclination separate from the carpenter, just as a gondola’s inclination is separate from the inclination of the cable that supports it. As there is no friction from below, gravity can do what it does best, and the gondola finds its natural inclination.

Surface vehicles are the exact opposite. Because their support comes from below, they cannot float free. A surface vehicle’s inclination is exactly the same as the road, track or rail it is supported on. This problem is as common to Cable Cars and Funiculars as it is to Buses, Subways and Light Rail. This makes sharp changes in inclination uncomfortable for riders (particularly standees), and technologically difficult for traditional technologies themselves.

That’s why roads, rails and tracks are typically inclined at a maximum 10 percent inclination. But doing this adds large costs to any bridges or tunnels required because the total ascent and descent must be “stretched-out” so that it doesn’t eclipse the 10 percent limit. The greater the total change in elevation, the greater the stretching-out.

This, of course, adds significantly to the amount of infrastructure required which adds additional cost while damaging the street level urban fabric. Furthermore, streetcars, subways, or any other rail-based technology simply cannot ascend a greater than 10 percent inclination due to a lack of traction and this “stretching-out” becomes an absolute prerequisite.

(Note: After additional research, I’ve found that a 10 percent inclination is typically too high for most urban rail systems, though there have been a few examples. The ability of any train to ascend such an inclination is dependent on the power of the motor and the speed of the train prior to its ascent. The descent is even more difficult. Bad weather significantly decreases a rail vehicle’s ability to deal with high gradients.)

A blue hybrid vehicle crossing a river. Image by Steven Dale

(Note: Some rail-based trains have solved the 10 Degree Problem using what is known as a Rack-Railway.)

Hybrids dispense with “stretched-out” bridges and tunnels. Hybrids disregard the 10 Degree Problem and nimbly leapfrog over (or groundhog under) impediments and intersections with ease. That saves money and does not clutter the streetscape with additional infrastructure. It also means that Hybrids could provide the first true fully-dedicated street level right-of-way, something Light Rail has never been able to accomplish.

Contemporary Light Rail systems operate in what are known as semi-dedicated rights-of-way. Mid-block they operate in their own exclusive rights-of-way, but at intersections they must contend with traffic, pedestrians and cyclists like everyone else. These semi-dedicated rights-of-way are meant to be an improvement on simple mixed traffic operations but statistics show little if any improvements because it is in the intersections where most problems occur, not at mid-block.

It’s a “weakest link” kind of problem and the weakest link in any right-of-way is always the intersection. If a right-of-way does not provide a vehicle exclusive access through, above or below the intersection, that right-of-way is virtually useless. This situation is common to semi-dedicated rights-of-way and are little more than a cosmetic frill that steals road space from private automobiles and cyclists. Some cities have experimented with Transit Signal Priority schemes to correct for this problem, but those schemes have yielded questionable results and a dubious track record.

Hybrids therefore present an intriguing possibility: Vehicles could run mid-block at street level in dedicated rights-of-way. This eliminates the cost of tunneling or elevating an entire line while contributing positively to the streetscape. Come the intersection, however, the vehicles could groundhog under or leapfrog over the problem, thereby preserving the fully-dedicated right-of-way.

This would, in turn, also allow the systems to be fully-automated, an impossibility with semi-dedicated rights-of-way. As was demonstrated by the Hungerburbahn, stations could even be located underneath the intersection, an ideal configuration for all.

A hybrid vehicle enters an inclined tunnel. Notice how the roof of the vehicle is still level despite the chassis's inclination. Image by Steven Dale.

The Hungerburgbahn may not be the silver bullet system cable’s waiting for, but it’s Hybrid configuration is a quantum leap forward for Cable Propelled Transit. While they are admittedly rare, they should not be ignored. Cable Hybrids can finally help transit planners realize their goal of a low-cost, fully-automated system that operates at ground level.

For that reason, Hybrids deserve a ton of respect and a whole lot of attention.

Want more? Purchase Cable Car Confidential: The Essential Guide to Cable Cars, Urban Gondolas & Cable Propelled Transit and start learning about the world's fastest growing transportation technologies.



The Hungerburgbahn (Part 2)

Hungerburgbahn, Alpenzoo Intermediary Station. Image by Steven Dale

This is Part 2 of a 3 Part series of posts on the Innsbruck Hungerburgbahn. To read Part 1, click here and to read Part 3, click here.

Leaving the technology-side of things until tomorrow’s post, let’s talk about the Hungerburgbahn’s station configuration.

A common misconception about cable transit is that the stations are large and are, therefore, incompatible with an urban environment. Fortunately this is just a misconception.

The Hungerburgbahn demonstrates how cable stations can be elegantly woven into the urban fabric. Whatever your opinions about Zaha Hadid’s intriguing design (my partner describes it as ugly play-dough from the future), these stations do not impose themselves on the city.

Intermediary Station, Löwenhaus, Image by Steven Dale

Terminals use a beguiling Open-Air-Yet-Underground (OAYU) design and the two intermediary stations are slim and provide ample space for bicycle parking. While the intermediary stations are two stories high, there is no reason they could not be placed on medians at street level much like the current practice common to Light Rail station infrastructure.

Above-Ground Entrance to the Congress Terminal (Exterior), Image by Steven Dale

Underground Congress Terminal (Interior), Image by Steven Dale

To understand cable, you have to divorce the infrastructure from the architecture. Cable infrastructure is relatively modest in size and can be located virtually anywhere (even a few stories underground). The architecture that encases the infrastructure, however, tends not to be. Not because it must be that way, but because it tends to be that way. Strip away the architecture and you have a minimal station footprint, which is highly desirable in urban environments. That’s why the Hungerburgbahn is so important: The stations are small and converse with the city beautifully.

Most alpine cable installations (which are the ones most are familiar with) have just two terminals and (possibly) a mid station. These terminals double as maintenance bays and car yards for the vehicles themselves. This automatically drives up the station size. So a minimum of one large-footprint terminal for maintenance and storage are a base requirement for cable, but intermediary stations can be as slim as desired.

Intermediary Station, Löwenhaus, Image by Steven Dale

Subways, Buses and Light Rail have the exact same problem, but their maintenance facilities tend to be located off-terminal. This “hides” the large footprint of traditional transit, but it does not eliminate it. Furthermore, traditional transit’s off-terminal maintenance configuration means significant costs are incurred to build the infrastructure necessary to shuttle vehicles to and from maintenance yards. A further cost is also incurred during daily operations to bring vehicles into service from the maintenance facilities. In-motion-but-out-of-service vehicles are common to all traditional transit technologies and are an inefficient and costly waste of resources that does not occur with cable transit.

Continue to Part 3.

Want more? Purchase Cable Car Confidential: The Essential Guide to Cable Cars, Urban Gondolas & Cable Propelled Transit and start learning about the world's fastest growing transportation technologies.



The Hungerburgbahn (Part 1)

Image by Steven Dale

Last month I toured the Hungerburgbahn CPT system in Innsbruck, Austria. There is much to say about this system, so I’ve broken the column into 3 parts. This is Part 1.

The importance of the Hungerburgbahn in Innsbruck, Austria cannot be overstated.  Given its unique Hybrid Funicular technology and elegant organic station design by renowned architect Zaha Hadid, one might expect this system to provoke the transit industry’s interest.

One would, however, be wrong: The system is virtually unknown outside this small city nestled in the Austrian Alps. That needs to change, however, because Hybrid Funiculars are a legitimate game-changer in the field of transit planning. Like it’s lone counterpart in Neuchåtel, Switzerland, the Hungerburgbahn deserves attention from the transit and planning industries.

Politicians and policy-makers suffer from what I call the No City Wants To Be First, Every City Wants To Be Second Problem. Traditional transit technologies exploit this problem masterfully because no matter what city you’re in, buses look like buses, subways look like subways and light rail looks like light rail. There are no surpises. Traditional transit technologies are easy to explain and simple to understand which makes life easy for time-deprived politicians and policy-makers.

In the political arena, cable is therefore at a disadvantage. Unless you’re trained to see the similarities, no two CPT systems look the same, at least not in urban environments.

Furthermore, successful implementation of cable in urban settings requires planners to pull component parts from each system and assemble their own. If transit planning were a toy store, buses, streetcars and subways would be the exact replica models, no assembly required. Cable, on the other hand, would be a big box of Lego with no instruction manual. With cable, there’s just no “silver bullet” installation that politicians and policy-makers can point to and say “yes! That’s exactly what we want!”

The Hungerburgbahn might just be that first silver bullet installation, or at least a stepping stone towards it. But before discussing what the Hungerburgbahn is, let’s discuss what it’s not:

  • The Hungerburgbahn is not fully-integrated into the city’s transit grid; an additional fare is required beyond the price of a standard transit ticket and that fare is not cheap: a steep €6.80.
  • The Hungerburgbahn is not a long system. It’s just under two kilometers long, with two stations, two terminals and only two vehicles which shuttle back-and-forth.
  • The Hungerburgbahn has atrociously long wait times of 15 minutes between departing vehicles. As the system caters to recreationalists (let’s pretend that’s a word, okay?), that is not such a problem, but would be in actual public transit usage. This could easily be shortened, however, as the travel time from end-to-end, is only 8 minutes.
  • Dwell times at stations and terminals are similarly long and unnecessary. I witnessed dwell times of up to two minutes at each of the two intermediary stations and cannot fathom a reasonable justification for this. Subways, which move hundreds of people at a time, use dwell times of between 10-20 seconds. Trimming dwell times could cut total travel time by up to 50%.

In other words, the Hungerburgbahn is not quite public transit. It is a stand-alone system that shuttles people from the city centre of Innsbruck to the alpine suburb of Hungerburg. But that is not the fault of the technology itself and none of the problems I just highlighted are specific to the technology. Each flaw the Hungerburgbahn presents is easily fixed.

So why then is the Hungerburgbahn such a revolutionary system? Tune in tomorrow to find out.

Hint: It has to do with the stations.

Continue to Part 2.

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