Thyssenkrupp Tests Cable-Free Multi Lifts That Travel Horizontally

Tom Scott

While linear induction drives eliminate structural cable limits in skyscrapers, convincing risk-averse developers to adopt the costly infrastructure poses a steeper hurdle than solving the engineering.

AI-assisted summary of An elevator that actually goes sideways — original source. Check the original for full context.

Source published: 2017-06-26

Key ideas

Thyssenkrupp has engineered 'Multi,' a cable-free elevator system capable of independent vertical and horizontal movement, tested in a dedicated 246-meter tower in Germany. (0:00)
The design eliminates steel hoist cables in favor of permanent-magnet linear induction motors, bypassing the structural weight limits that constrain elevators in ultratall skyscrapers. (0:58)
Cabins switch between vertical travel and horizontal transit using mechanical 'exchangers' that physically rotate the guide tracks at shaft junctions. (0:58)
Because linear motor infrastructure adds substantial weight and expense, cabins are built from carbon fiber and aluminum, with safety brakes mounted directly on the cars. (2:15)

Detailed notes

## Background Published on YouTube by Tom Scott on June 26, 2017, the video documents his visit to Thyssenkrupp's test facility in Germany to see their Multi elevator system. After previously covering a paternoster lift and a hybrid sideways elevator in Genoa, Scott accepted an offer from Thyssenkrupp to tour their newly built test tower and observe a fully multidirectional elevator operating without vertical cables.

## TL;DR Tom Scott tours Thyssenkrupp's 246-meter elevator test tower in Germany to inspect Multi, an elevator system capable of both vertical and horizontal transit. Bypassing the height and weight limits of traditional steel cables, the system uses permanent-magnet linear induction motors and rotating track exchangers that transfer lightweight carbon fiber cabins between shafts in a continuous loop. Although the system incorporates independent onboard brakes and rigorous safety interlocks, its primary remaining challenge lies in convincing risk-averse skyscraper developers to invest in the costly, complex shaft infrastructure.

## Atmosphere & style The video carries an inquisitive, enthusiastic tone characteristic of Tom Scott's explorations into novel engineering feats. Moving through the echoing, cavernous shafts of the massive test tower alongside Thyssenkrupp engineers gives the demonstration a palpable sense of futuristic wonder grounded in physical reality. The narrative balances excitement over rotating track switches and cable-free propulsion with a pragmatic, analytical look at the economic hurdles and strict regulatory realities of the elevator industry.

## Bulletin - [00:00](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=0s) Thyssenkrupp has engineered 'Multi,' a cable-free elevator system capable of independent vertical and horizontal movement, tested in a dedicated 246-meter tower in Germany. - [00:58](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=58s) The design eliminates steel hoist cables in favor of permanent-magnet linear induction motors, bypassing the structural weight limits that constrain elevators in ultratall skyscrapers. - [00:58](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=58s) Cabins switch between vertical travel and horizontal transit using mechanical 'exchangers' that physically rotate the guide tracks at shaft junctions. - [02:15](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=135s) Because linear motor infrastructure adds substantial weight and expense, cabins are built from carbon fiber and aluminum, with safety brakes mounted directly on the cars.

## Key takeaways - [00:00](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=0s) Unlike previous systems that cheated horizontal travel by placing a smaller vehicle inside a vertical frame, Multi achieves genuine multi-axis transit without external carrier cabs. - [00:00](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=0s) Thyssenkrupp built a 246-meter-tall test tower with 1,700 steps to rigorously evaluate Multi rather than testing prototype systems on client sites. - [00:58](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=58s) Multi revives the core efficiency of obsolete paternoster lifts by running multiple circulating cabins simultaneously in a continuous loop. - [00:58](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=58s) The exchanger mechanism physically rotates the drive tracks at intersections, redirecting moving cabins horizontally into adjacent shafts. - [00:58](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=58s) Conventional skyscraper elevators hit strict physical limits where long steel cables become too heavy to support their own dead weight. - [00:58](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=58s) Cable-free propulsion is accomplished by unrolling traditional rotary motors into flat linear induction drives lining the shafts. - [02:15](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=135s) Safety braking systems have been redesigned to sit directly on individual cabins rather than within a traditional machine room at the top of the shaft. - [02:15](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=135s) Safety interlocks constantly verify the position and lock state of each exchanger, triggering an immediate safe stop if operating limits are violated. - [02:15](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=135s) To counter the heavy weight of linear induction motors, cabin structures are manufactured from lightweight aluminum and carbon fiber. - [02:15](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=135s) Lining entire shaft networks with powered magnetic coils presents significant manufacturing, installation, and capital cost challenges. - [02:15](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=135s) Commercial success depends on convincing notoriously risk-averse skyscraper developers to adopt an unprecedented elevator paradigm.

## Detailed walkthrough ### [00:00](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=0s) The Quest for a Sideways Elevator and the Test Tower

Tom Scott recounts his ongoing journey exploring unconventional elevator designs over successive summers. In June 2015, he visited Sheffield to see a paternoster lift—an obsolete elevator mechanism made of a continuous looping chain of open compartments. In June 2016, he traveled to Genoa, Italy, to see an elevator system capable of sideways motion, although Scott notes that setup was essentially a cheat: a small horizontal car riding inside a larger vertical elevator that handled the heavy lifting. By June 2017, he arrived at the newly built Thyssenkrupp Elevator Test Tower in Germany. Thyssenkrupp flew him out to reveal Multi: an actual, full-size, working elevator system engineered to traverse sideways without any shortcuts.

Inside the facility, a Thyssenkrupp engineer explains the critical role of the test tower, stating: “For us, it was very important to have a tower to test the new technology. We don't want to test it at the customers' site.” The testing structure is massive, standing 246 meters tall and containing 1,700 steps—a detail the engineer knows firsthand, having walked up the entire staircase once. The facility functions almost entirely as a cluster of elevator shafts, balancing standard testing for traditional lifts alongside dedicated shafts reserved strictly for the Multi system.

- **Paternoster lift (Sheffield, June 2015):** Looping chain of open cabs. - **Genoa system (Italy, June 2016):** Horizontal passenger cabin carried within a standard vertical elevator frame. - **Thyssenkrupp Multi (Germany, June 2017):** True multidirectional elevator capable of vertical and horizontal movement. - **Test Tower Dimensions:** 246 meters high with 1,700 staircase steps.

[00:58](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=58s) The Exchanger Mechanism and Linear Induction Drives

The foundational concept behind Multi revives an early ideal of elevator engineering: maintaining a continuous, rotating flow of cabins. As a Thyssenkrupp engineer highlights: “The principle of having a continuous rotating flow of cars was one of the best inventions in our industry ever.” To realize this, the system transfers cabins between parallel shafts using a specialized mechanism called an exchanger. Mounted at key junctions within the shafts, the exchanger physically rotates the guide track, redirecting a descending or ascending cabin straight into horizontal transit across to another shaft. These exchangers can be situated at any point in a building's shaft network, enabling highly versatile architectural layouts.

```mermaid flowchart TD accTitle: Multi Elevator Cabin Routing accDescr: Flow diagram showing how elevator cabins travel vertically, rotate at an exchanger, and move horizontally into another shaft. subgraph Shaft_A["Vertical Shaft A"] VDown["Cabin travels vertically"] end subgraph Exchange_Bay["Shaft Junction"] Exchanger["Exchanger Mechanism<br/>Rotates drive tracks"] end subgraph Shaft_B["Vertical Shaft B"] HMove["Horizontal transit"] VUp["Cabin moves into vertical run"] end

VDown --> Exchanger Exchanger --> HMove HMove --> VUp ```

A severe constraint of traditional elevators in ultratall skyscrapers is the vertical cable: past certain heights, a steel cable becomes so long and heavy that it cannot even support its own dead weight, let alone the load of an attached cabin. Multi bypasses cables entirely by using linear induction motors. A representative explains the propulsion mechanism by drawing a comparison to standard motors: “If we just take this motor and cut it on one side and just lay it on a table flat, then you already have a linear drive.” These permanent-magnet synchronous linear drives line the pathways in both vertical and horizontal directions, pushing and pulling cabins electromagnetically.

- **Continuous cabin loop:** Eliminates dead wait time by circulating multiple cabs through linked shafts. - **Exchanger system:** Pivotable track segment that shifts the cabin from vertical rails to horizontal guide paths. - **Cables eliminated:** Bypasses skyscraper cable-weight physics limits via linear induction synchronous motors.

[02:15](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=135s) Safety Systems, Engineering Trade-Offs, and Commercial Hurdles

Traditional traction elevators rely on multiple redundant steel cables—any single one of which can bear more than the design load—alongside deployable friction brakes and bottom buffers designed to downgrade a catastrophic freefall from fatal to survivable. Because passenger elevators are among the most heavily regulated systems in existence, Multi must meet or exceed those stringent safety margins before welcoming the public. A Thyssenkrupp engineer points out a fundamental architectural shift in safety design: “In conventional elevators, you have the brake on the machine on top of the shaft in the machine room; now we have the brake directly on the cars.” Furthermore, safety controllers constantly verify the exchanger status—verifying whether it is properly positioned and locked—and immediately force the elevator into a safe state if any operating rule is breached.

However, the technology introduces substantial engineering and economic hurdles. Linear induction motors are exceptionally heavy and costly to produce. Every individual cabin must be equipped with its own motor drive, and the entire height and breadth of the shaft network must be fitted with magnetic coil tracks to supply power and propulsion. To offset this equipment weight, Thyssenkrupp manufactures the elevator cabs out of lightweight carbon fiber and aluminum. While mathematical models and tower testing show great promise, the ultimate hurdle is commercial adoption. Scott emphasizes that Thyssenkrupp must now convince major skyscraper developers—who are notoriously risk-averse—to purchase the system: “And that might be a greater challenge than making the elevators in the first place.”

- **Onboard Braking:** Traditional machinery-room brakes are replaced with autonomous emergency braking hardware mounted directly on each cab. - **Exchanger Interlocks:** System safety controllers poll lock engagement and position before allowing cabin passage. - **Material Construction:** Cabins utilize carbon fiber and aluminum composites to counteract heavy linear motor assemblies. - **Shaft Infrastructure:** Full shaft runs must be lined with powered magnetic coils.

## Notable quotes > [00:58](https://www.youtube.com/watch?v=kdTsbFS4xmI&t=58s) The principle of having a continuous rotating flow of cars was one of the best inventions in our industry ever. — Thyssenkrupp engineer

## Mentioned Tom Scott, Thyssenkrupp, Multi, Thyssenkrupp Elevator Test Tower, Sheffield, Genoa, Germany, Michelle Martin, Lateral, The Technical Difficulties, Tom Scott Plus

## Video description I've filmed a paternoster lift; I've filmed the strange Genoa elevator that sort-of goes sideways. So when I got an email from Thyssenkrupp, an elevator company, saying "come and see our Multi elevator that actually goes sideways", I wasn't going to turn it down.

Full disclosure: Thyssenkrupp paid for my travel to Germany, but that's all they did. I'd got in touch with them last year asking to see this when it opened; their PR firm replied, offering to fly me out. They had no editorial control over this, and didn't get to see it before it was uploaded!

More information about Multi: https://multi.thyssenkrupp-elevator.com/en/

Thanks to Michelle Martin https://www.youtube.com/@OnTheCrux for help editing the interviews!

🟥 MORE FROM TOM: https://www.tomscott.com/ (you can find contact details and social links there too) ❓ LATERAL, free weekly podcast: https://lateralcast.com/ https://youtube.com/lateralcast/ ➕ TOM SCOTT PLUS: https://youtube.com/tomscottplus 👥 THE TECHNICAL DIFFICULTIES: https://youtube.com/techdif

[Source](https://www.youtube.com/watch?v=kdTsbFS4xmI)

中文简报

蒂森克虏伯测试可水平运行的无缆绳Multi电梯尽管线性感应驱动消除了摩天大楼中缆绳的结构限制，但说服规避风险的开发商采用这种昂贵的基础设施，比解决工程难题面临更大的阻碍。 Tom Scott参观了蒂森克虏伯位于德国的246米电梯测试塔，以实地考察具备垂直和水平运输能力的电梯系统Multi。该系统突破了传统钢缆的高度和重量限制，采用永磁线性感应电机和旋转式轨道转换机构，使轻质碳纤维轿厢能在不同井道之间以连续循环的方式转移。尽管该系统配备了独立的车载制动装置和严格的安全联锁系统，但其当前面临的主要挑战仍是说服规避风险的摩天大楼开发商投资于这套昂贵且复杂的井道基础设施。蒂森克虏伯设计出了名为“Multi”的无缆绳电梯系统，能够实现独立的垂直与水平移动，并在德国一座专用的246米测试塔中进行了测试。 (0:00) 该设计摒弃了钢制提升缆绳，转而采用永磁线性感应电机，突破了限制超高层摩天大楼电梯的结构重量上限。 (0:58) 轿厢通过机械“转换装置”在垂直运行和水平运输之间切换，该装置可在井道交汇处通过物理方式旋转导轨。 (0:58) 由于线性电机基础设施增加了相当大的重量和成本，轿厢采用碳纤维和铝材制成，安全制动装置则直接安装在轿厢上。 (2:15)

Reading summary

Thyssenkrupp's Multi elevator system eliminates vertical hoist cables by utilizing linear induction motors and rotating track exchangers, allowing multiple cabins to travel both vertically and horizontally in a continuous loop. Linear Induction and Cable-Free Motion (0:58) In conventional ultratall skyscrapers, standard steel cables eventually reach a physical limit where the cable becomes too heavy to support its own dead weight alongside a loaded cabin. Thyssenkrupp bypasses this height constraint by eliminating cables entirely in favor of permanent-magnet synchronous linear induction motors. Functioning essentially as conventional motors flattened along the walls, these linear drives push and pull cabins electromagnetically in both vertical and horizontal directions. This architecture revives the early elevator concept of a continuous rotating flow of cars, previously seen in early designs like Sheffield's 2015 paternoster lift. Rather than confining a single elevator car to an isolated vertical run, the linear induction drive enables several autonomous cabins to circulate through the same network simultaneously. Directional Routing via Rotating Exchangers (0:58) Multidirectional movement relies on mechanical junctions known as exchangers positioned between parallel shafts. When a cabin reaches an exchange bay, the exchanger physically pivots the guide track, realigning the car's orientation from vertical travel directly into a horizontal transit corridor connecting adjacent shafts. Because these exchangers can be installed at arbitrary levels across a building, architects can design interconnected circulation pathways rather than simple vertical lines. Cabins can ascend in one shaft, switch tracks across a horizontal hallway, and descend via an alternate shaft to reduce dwell times. Decentralized Braking and Safety Systems (2:15) Passenger elevators operate under strict regulatory safety mandates that traditionally rely on machine-room friction brakes, redundant load-bearing cables, and pit buffers designed to absorb impacts. Because Multi removes hoist cables and overhead machine rooms, Thyssenkrupp relocated the braking hardware directly onto each individual cabin, providing autonomous stopping power. System safety controllers also continuously supervise the physical state of the track exchangers. The control network verifies that the exchanger track is accurately aligned and mechanically locked into place before permitting a cabin to traverse the junction, immediately enforcing a safe stop if an anomaly or operating rule breach occurs. Material Offsets and Commercial Hurdles (2:15) Implementing linear induction creates significant technical and financial trade-offs. The linear drives add substantial weight to each car, while every shaft must be lined with powered magnetic coil tracks. To counteract the heavy drive hardware, Thyssenkrupp fabricates the cabins from lightweight carbon fiber and aluminum composites. Although Thyssenkrupp validated the hardware in an isolated 246-meter, 1,700-step test tower in Germany to avoid testing in client facilities, commercial adoption remains uncertain. Tom Scott highlights that convincing typically risk-averse skyscraper developers to finance and install an unproven, capital-intensive elevator infrastructure may present a greater hurdle than the underlying engineering. Multi demonstrates a functional method to bypass the mechanical height limits of standard cable elevators, but its widespread adoption depends on whether commercial developers will accept the high equipment costs and unproven operational track record of magnetic shaft networks.

精炼阅读摘要

根据Tom Scott的实地探访与Thyssenkrupp工程师的介绍，Thyssenkrupp研发的Multi电梯系统通过直线电机与导轨转向装置摆脱了传统钢缆束缚，实现了轿厢的水平与垂直多向连续运行，但其商业化推广仍面临高昂成本与开发商避险心态的考验。高塔测试与无缆驱动构想 (0:00) 传统高层建筑电梯高度受制于钢缆物理极限，当建筑达到超高层时，钢缆自重过大甚至无法支撑自身重量，更不用说悬挂轿厢。Thyssenkrupp在德国建造了一座高246米、拥有1700级台阶的电梯测试塔，专门用于在非客户现场验证全尺寸的多向电梯系统Multi。工程师表示测试塔的作用在于避免将未经检验的新技术直接带入实际项目。转向机构与直线感应驱动技术 (0:58) Multi系统的核心构想借鉴了连续循环运作的电梯理念，通过在平行井道间布置名为“转换器”（exchanger）的机械转向装置，物理旋转导轨，将轿厢从垂直升降无缝引导至横向平移。工程师认为连续循环的轿厢流是行业关键创新之一，这种转向设计可布置在建筑井道的任意位置，为建筑布局提供了极高的灵活性。在动力层面，Multi完全放弃了传统悬吊钢缆，转而采用永磁同步直线感应电机驱动。工程师解释其原理类似于将传统电机的定子展开铺平。垂直与水平轨道全线铺设磁性线圈轨道，通过电磁力直接推动和吸引轿厢，从而打破了垂直钢缆对建筑高度与轿厢数量的限制。重构的安全体系与工程权衡 (2:15) 鉴于客运电梯受到极严苛的安全监管，Multi重构了传统的机房制动架构。工程师指出，传统电梯将制动装置设于井道顶部的机房中，而Multi直接在每个轿厢上安装了自主紧急制动硬件。同时，安全控制器会实时检测转向装置的定位与锁定状态，一旦触发任何违规或异常状态，系统便强制切入安全模式。然而，直线电机的应用带来了高昂的制造成本与巨大的设备自重。为抵消电机和磁性导轨带来的重量负担，Thyssenkrupp采用碳纤维与铝合金复合材料来打造轻量化轿厢，且井道全长均需铺设带电磁轨，大幅推高了基础设施建设与维护的复杂度。尽管数学模型与测试塔试验验证了Multi的技术可行性，但Scott指出，该系统面临的最大挑战在于商业落地。对于普遍极度规避风险的摩天大楼开发商而言，说服他们采购造价高昂且打破常规的无缆电梯系统，其难度甚至可能超过研发电梯本身的工程挑战。

Source quotes

[0:58] Thyssenkrupp engineer: The principle of having a continuous rotating flow of cars was one of the best inventions in our industry ever.

Original transcript

[0:00] In June 2015, I went to Sheffield, and I saw a paternoster lift, [0:03] an obsolete design of elevator with a looping chain of open cabs. [0:07] In June 2016, I travelled to Genoa in Italy, [0:10] and I saw an elevator that also moved sideways. [0:12] Except, spoiler, it's a bit of a cheat, [0:14] it's actually a little horizontal car [0:15] that moves inside a bigger elevator that does the heavy lifting. [0:18] And now, it is June 2017. [0:20] And I'm in Germany, at the brand-new Thyssenkrupp Elevator Test Tower, [0:24] and they have flown me out here to show off Multi: [0:27] their actual, full-size, working elevator [0:31] that moves sideways without cheating. [0:33] For us, it was very important to have a tower to test the new technology. [0:38] We don't want to test it at the customers' site. [0:40] The tower is 246m high, and this means 1,700 steps. [0:46] I know that exactly, because I walked up once! [0:50] This is a building made almost entirely of elevator shafts. [0:53] Some of them test regular lifts, [0:55] but some of them are reserved for this new system. [0:58] The principle of having a continuous rotating flow of cars [1:03] was one of the best inventions in our industry ever. [1:07] And to achieve this, we have to exchange cabins from one shaft to another. [1:14] And to have this exchange, we need an exchanger, [1:16] which you see just behind me. [1:18] And this exchanger allows us to go into horizontal movement. [1:22] The exchanger can be placed at every point in the shaft [1:25] so it allows us to do all kinds of configurations. [1:30] Coming down vertically, and then going into the horizontal movement. [1:35] One of the problems with elevators in really tall buildings [1:38] is that you need a cable so long that it can't support its own weight, [1:42] let alone the weight of the cab that's then connected to it. [1:45] The solution here is a bit different, and it doesn't use cables at all. [1:48] It uses linear induction motors. [1:51] Linear drive - it's also a synchronous motor with permanent magnets. [1:58] And you maybe know it from a rotating motor. [2:01] If we just take this motor and cut it on one side [2:06] and just lay it on a table flat, [2:09] then you already have a linear drive. [2:11] And this is what we have, vertical and also horizontal. [2:15] In a regular elevator, it's called a traction elevator, [2:18] you've got cables holding the cab, [2:20] any one of which can hold more than the design weight. [2:22] Also, you've got emergency brakes which will pop out [2:25] and slow the car down with friction if it's moving too fast. [2:28] And, absolute worst case, even if all that somehow fails, [2:32] you have a buffer at the bottom that should reduce a freefall drop [2:35] from "fatal" to just "severe injuries"(!) [2:38] Elevators are incredibly safe because they're incredibly well-regulated. [2:42] So before this is allowed to carry humans, [2:45] this system needs to be at least as failsafe. [2:48] The safety is not just in the ropes of a conventional elevator [2:52] but in the brake system. [2:53] In conventional elevators, you have the brake [2:56] on the machine on top of the shaft in the machine room [3:00] now we have the brake directly on the cars. [3:03] This new component, the exchanger, [3:05] where we go from vertical into horizontal movement, [3:09] also needs to be checked by our safety controller. [3:14] What is the position of the exchanger? [3:16] Is it locked? [3:17] Is it safe? [3:18] And in case of any violation of a safety rule, [3:23] then we go to a 'safe state'. [3:26] There are, of course, some catches. [3:28] Linear induction motors are expensive and heavy. [3:31] Each one of the cabs needs to have its own set. [3:33] And the whole elevator shaft, from top to bottom, [3:35] needs to be lined with the magnetic coil units that power them. [3:39] To save weight, these cabs are made of carbon fibre and aluminium. [3:43] So will it work out in the real world? [3:44] Thyssenkrupp's models say it will, [3:46] but everything's been tested and approved here, [3:48] the next step is to sell it. [3:50] To the kind of enormous multinational companies who build skyscrapers [3:53] and who do not like risk. [3:55] And that might be a greater challenge than making the elevators in the first place. [4:00] Thank you very much to all the team at Thyssenkrupp who've invited me over here. [4:03] You can pull down the description for more about Multi.