# Is it possible to build a working spiral escalator? **URL:** \ **Category:** Factual Questions\ **Created:** [September 20, 2006, 1:27pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409 "2006-09-20T13:27:22Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![nemminie](https://avatars.discourse-cdn.com/v4/letter/n/ecb155/32.png) [@nemminie](https://boards.straightdope.com/u/nemminie)\ **Post date:** [September 20, 2006, 1:27pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/1 "2006-09-20T13:27:22Z")
Which is a helical moving staircase, within a tube rather than the conventional inclined plane. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 20, 2006, 1:30pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/2 "2006-09-20T13:30:49Z")
Yes. Already been done. > [@](#): > > Spiral escalators take up much less horizontal space than straight escalators. However, early spiral designs were failures. For example, one spiral escalator constructed by Reno in conjunction with William Henry Aston at London’s Holloway Road Underground station in 1906 [[1]] was dismantled almost immediately and little of the mechanism survives. The Mitsubishi Electric Corporation has developed successful commercial designs and has manufactured curved and spiral escalators since the 1980s. > > Notable sets of spiral escalators are located in the San Francisco Shopping Centre in San Francisco, California, and at Forum Shops at Caesars Palace in Las Vegas, Nevada. The Times Square shopping mall in Causeway Bay, Hong Kong, also features four curved escalators, as does Wheelock Place in Singapore. > > SOURCE: [Escalator - Wikipedia](http://en.wikipedia.org/wiki/Escalator) Here’s a picture of one: [Spiral Escalator | There are very few of these in the world … | Flickr](http://www.flickr.com/photos/nhanusek/241514438/) ---
**Author:** ![Jodi](https://avatars.discourse-cdn.com/v4/letter/j/7feea3/32.png) [@Jodi](https://boards.straightdope.com/u/Jodi)\ **Post date:** [September 20, 2006, 1:43pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/3 "2006-09-20T13:43:34Z")
I was going to post to say I know they can, because there’s one in the Shops at Caesar’s Forum in Las Vegas, and that’s the one **Whack-a-Mole** has linked to. 🙂 ---
**Author:** ![bordelond](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bordelond/32/150_2.png) [@bordelond](https://boards.straightdope.com/u/bordelond)\ **Post date:** [September 20, 2006, 1:54pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/4 "2006-09-20T13:54:36Z")
I’m assuming the escalator steps essentially go up a giant screw. But how do they come back down? I suppose they can enter some kind of side chamber and just be directed downwards. But then you have to have steps that’ll work with the screw support, and then also work with some linear mechanism for returning them to the ground. The engineering of these escalators must be amazing. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [September 20, 2006, 2:39pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/5 "2006-09-20T14:39:45Z")
I’ve been on a curved escalator at Nordstrom’s in San Francisco. The steps appear to be horizontally wedge-shaped. This is fine as they go up, but if they come down underneath, in the same way as straight escalators, their narrow sides are probably separated or spread apart at some point. ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [September 20, 2006, 2:45pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/6 "2006-09-20T14:45:10Z")
[QUOTE=bordelond] I’m assuming the escalator steps essentially go up a giant screw. [/QUOTE] I don’t think so. I’ve seen the ones in San Francisco (and **Whack-a-Mole** ’s link confirms); they don’t describe a full circle (as seen from above) and there’s empty space in the center of the arc where the screw would have to be. Or did you mean a flexible shaft (like a speedometer cable) acting as a worm gear under the steps? I think it probably works just like a regular escalator (diagrams [here](http://science.howstuffworks.com/escalator1.htm) and [here](http://www.kenseamedia.com/encyclopedia/eee/how_escalator_works_2.htm)) but with the steps and tracks custom made for the particular amount of curvature. It seems to me it’s just a matter of getting the drive chain, the steps and the hand rails to run on curved guide tracks without binding up. ---
**Author:** ![iamthewalrus\_3](https://avatars.discourse-cdn.com/v4/letter/i/258eb7/32.png) [@iamthewalrus\_3](https://boards.straightdope.com/u/iamthewalrus_3)\ **Post date:** [September 20, 2006, 6:03pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/7 "2006-09-20T18:03:31Z")
[QUOTE=bordelond] I’m assuming the escalator steps essentially go up a giant screw. But how do they come back down? I suppose they can enter some kind of side chamber and just be directed downwards. But then you have to have steps that’ll work with the screw support, and then also work with some linear mechanism for returning them to the ground. [/QUOTE] Why couldn’t the steps just fold over and go back down the underside of the track (like I assume normal escalators do)? It’ just be a big conveyor belt that’s been twisted. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [September 20, 2006, 6:28pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/8 "2006-09-20T18:28:38Z")
[QUOTE=iamthewalrus(:3=] Why couldn’t the steps just fold over and go back down the underside of the track (like I assume normal escalators do)? It’ just be a big conveyor belt that’s been twisted. [/QUOTE] I _was_ going to say that, from the viewpoint of the steps, they are now curving in the opposite direction and their wedge shape would be opposite to what is needed. But then I realised that the returning steps would also be _upside-down_, and their wedge shape would still be appropriate. At the ends of the escalator, though, special arrangements would need to be made. The “combs” or whatever they are called, on the top of the steps and at the edge of the landing platforms, are curved, IIRC, and this curve would have to be maintained until the steps are completely underneath the landing platforms and can be redirected. I suspect that all the curving escalators made have a single constant curvature, and all the steps and such are custom-made to suit that curvature. Builsding an escalator to do a reverse curve would be a _lot_ harder. ---
**Author:** ![Ike\_Witt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ike_witt/32/283_2.png) [@Ike\_Witt](https://boards.straightdope.com/u/Ike_Witt)\ **Post date:** [September 20, 2006, 6:44pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/9 "2006-09-20T18:44:44Z")
I think that the curved escalator was developed by Mitsubishi. [Here](http://www.mitsubishi.or.jp/e/monitor/0512/story.html) is a story on it. > [@](#): > > The steps must remain horizontal and evenly spaced as they move through the length of the escalator. This seemed to be way too difficult to be applied in the twisting motion. But our team never gave up. Finally, we made a breakthrough—we were the first to see this requires different radii of curvature for horizontal and inclined sections and invented and patented a totally new core mechanism. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [September 20, 2006, 6:58pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/10 "2006-09-20T18:58:54Z")
[Mitsubishi](http://www.mitsubishi-elevator.com/products/basic/escalators/spiral_es/index.html) makes all of the spiral escalators out there. They’ve got some PDF scans of brochures and installation specs, but nothing really giving details. The patent text is [here](http://patft.uspto.gov/netacgi/nph-Parser?u=%2Fnetahtml%2Fsrchnum.htm&Sect1=PTO1&Sect2=HITOFF&p=1&r=1&l=50&f=G&d=PALL&s1=5165513.PN.&OS=PN/5165513&RS=PN/5165513). To see the images, you’ll need the free “AlternaTIFF” plugin. (Click the red “help” in the yellow titlebar for more info) Unfortunately, the images aren’t all that useful for visualizing the mechanism. ---
**Author:** ![nemminie](https://avatars.discourse-cdn.com/v4/letter/n/ecb155/32.png) [@nemminie](https://boards.straightdope.com/u/nemminie)\ **Post date:** [September 20, 2006, 7:11pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/11 "2006-09-20T19:11:50Z")
The Mitsubishi web page gives no detail unfortunately. I see the Forum Shops at Caesars Palace escalators ‘only’ twist 180°. That’s very impressive, but I was really thinking about the general solution where any number of twists can be employed, up the tube all the way to the top. If that can be built that would be _extremely_ impressive. Probably, if it’s not in Dubai already then it can’t be built. ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [September 20, 2006, 7:51pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/12 "2006-09-20T19:51:43Z")
Well, the slope of an escalator is already determined (by expectations and probably building codes), the floors of the Forum Shops are a certain distance apart, and I would imagine there’s some minimum radius of curvature for the escalator. I can’t see any reason why a spiral escalator couldn’t make a full circle, but there just aren’t many places that need one with enough altitude change. I still read and hear about plans for a subway/light rail system in Seattle. One of the snags is that the obvious route from downtown is to go east under Capital Hill, then northbound under broadway to the U District. But subways and trolleys are very limited in the grades they can climb, and even at their best the first Capital Hill stop would be more than a hundred feet underground. That usually means long runs of stairs and escalators. I wonder if they’ve thought of a round shaft with spiral escalators and stairs. ---
**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\ **Post date:** [September 20, 2006, 8:04pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/13 "2006-09-20T20:04:08Z")
[QUOTE=Robot Arm] I still read and hear about plans for a subway/light rail system in Seattle. One of the snags is that the obvious route from downtown is to go east under Capital Hill, then northbound under broadway to the U District. But subways and trolleys are very limited in the grades they can climb, and even at their best the first Capital Hill stop would be more than a hundred feet underground. That usually means long runs of stairs and escalators. I wonder if they’ve thought of a round shaft with spiral escalators and stairs. [/QUOTE] Firstly, light rail can cope with surprising slopes and curves. Secondly, I doubt there’s much difference in a cut-and-cover construction of a large escalator compared to a spiral one. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [September 20, 2006, 8:21pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/14 "2006-09-20T20:21:27Z")
Has anyone ever built an escalator that levels off and then resumes climbing? It would have a ‘landing’, where people could exit and enter sideways. ---
**Author:** ![Turek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/turek/32/18782_2.png) [@Turek](https://boards.straightdope.com/u/Turek)\ **Post date:** [September 20, 2006, 9:42pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/15 "2006-09-20T21:42:00Z")
[QUOTE=Sunspace] Has anyone ever built an escalator that levels off and then resumes climbing? It would have a ‘landing’, where people could exit and enter sideways. [/QUOTE] That seems like a solution in need of a problem. It’s much cheaper and easier to build an escalator, a flat stretch of floor, and then another escalator. No new design required. Not as “gee whiz” but more economical. Plus, stepping onto a surface moving sideways relative you to would be problematic for many people. ---
**Author:** ![sinjin](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@sinjin](https://boards.straightdope.com/u/sinjin)\ **Post date:** [September 21, 2006, 7:24am UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/16 "2006-09-21T07:24:24Z")
Alright, here’s the problem: build an escalator which allows young healthy people to travel from the first to the second or third floors but prohibits those frail elderly people on the second floor from getting on and visiting your 4//3Z()|V|@ icecream parlor on the third floor. Now all we need is someone to build us this kick-ass escalating wonder and we can enjoy our icecream in peace without having to look at all that wrinkly old people skin. 🙂 sinjin ---
**Author:** ![slaphead](https://avatars.discourse-cdn.com/v4/letter/s/e9bcb4/32.png) [@slaphead](https://boards.straightdope.com/u/slaphead)\ **Post date:** [September 21, 2006, 11:15am UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/17 "2006-09-21T11:15:40Z")
[QUOTE=Robot Arm] at their best the first Capital Hill stop would be more than a hundred feet underground. That usually means long runs of stairs and escalators. [/QUOTE] Why would that be a significant problem? The Bank platforms on the Docklands Light Railway are something like 130 feet underground, and it’s a relatively minor inconvenience. There is a station more than 190 feet down, but it uses a lift (elevator) if I recall correctly. It would be expensive to dig so deep, but providing there’s a bit of elbow room to put the shafts in, normal escalators would be A-OK. I think for very deep or narrow shafts, spiral stairs/escalators are a bad idea. If they are too narrow, the treads get extremely shallow (barely a toehold) towards the centre, and if they are too deep, you get dizzy by the time you reach the bottom. This may be why they were abandoned as soon as technology advanced beyond the 'sink a well and put a staircase in it" level. ---
**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\ **Post date:** [September 21, 2006, 12:24pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/18 "2006-09-21T12:24:30Z")
[QUOTE=slaphead] Why would that be a significant problem? The Bank platforms on the Docklands Light Railway are something like 130 feet underground, and it’s a relatively minor inconvenience. There is a station more than 190 feet down, but it uses a lift (elevator) if I recall correctly. [/quote] Yep, that’s Hampstead station. And Angel’s escalators have a vertical rise of 90ft. > [@](#): > > if they are too deep, you get dizzy by the time you reach the bottom. This may be why they were abandoned as soon as technology advanced beyond the 'sink a well and put a staircase in it" level. They were? Many tube stations were originally served by lifts, with escalators being fitted later on because they have a far greater capacity. The original street-level entrances were no longer in the correct place, and so new ones were built in different locations. (And in the case of the British Museum station on the Central line, it would have ended up so close to Holborn station that it was simpler to put in new platforms and tunnels connecting to there, closing the old station - hence the long walk when you change lines at Holborn) Plus, new stations such as Southwark and Canary Wharf have been built using escalators. ---
**Author:** ![slaphead](https://avatars.discourse-cdn.com/v4/letter/s/e9bcb4/32.png) [@slaphead](https://boards.straightdope.com/u/slaphead)\ **Post date:** [September 21, 2006, 1:58pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/19 "2006-09-21T13:58:58Z")
[QUOTE=GorillaMan] They were? Many tube stations were originally served by lifts, with escalators being fitted later on because they have a far greater capacity. [/QUOTE] My bad, I wasn’t clear enough. Spiral stairs were very widely used as standbys for those old lift stations. If you’ve ever used the stairs at somewhere like covent garden or at the Greenwich Foot Tunnel you should hopefully take my drift - they are really bloody awkward. I assume spiral escalators would suffer from the same problem, but to a lesser extent if they all have as wide a central gap as the one pictured. Straight escalators are easier to engineer and when not running turn into plain, if slightly awkward, stairs. Given the well-known “can’t walk down a stationary escalatory” syndrome, I imagine a stationary spiral escalator might be a bit of a challenge, especially after chucking-out time. ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [September 21, 2006, 2:15pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409/20 "2006-09-21T14:15:41Z")
[QUOTE=slaphead] Why would that be a significant problem? The Bank platforms on the Docklands Light Railway are something like 130 feet underground, and it’s a relatively minor inconvenience. There is a station more than 190 feet down, but it uses a lift (elevator) if I recall correctly. It would be expensive to dig so deep, but providing there’s a bit of elbow room to put the shafts in, normal escalators would be A-OK. [/QUOTE] It’s not an insurmountable problem, but it’s not ideal, either. I can think of a station on the Boston subway, and a couple on the D.C. metro that have very deep escalators. They’re all in slightly less built-up areas than Capital Hill, so there would have been more room for the necessary digging. Soil conditions probably play a role, too; when the Interstate 90 tunnel under Beacon Hill was built nearby it was the largest soft-earth tunnel in the world. One idea I’ve heard was for when the rail tunnel changes from east to north, instead of a 90-degree left turn, build it as a 270-degree, climbing right turn. [Next page](https://boards.straightdope.com/t/is-it-possible-to-build-a-working-spiral-escalator/373409.md?page=2)