Smart Glass On The Bukit Panjang LRT

Post by Steven Dale

I was more than a little impressed by the speed with which Gondola Project readers were able to identify the system I pointed out in this past weekend’s post.

Sure enough, as Mattias pointed out, the system in question was the Bukit Panjang LRT in Singapore. This wasn’t a system I’d ever heard of or ever planned on visiting. Instead, I just happened to stumble across it while visiting a few of Singapore’s transit amenities during a 14 hour stop over there.

Now let’s get this out of the way right off the bat: The Bukit Panjang isn’t an LRT. Not even close. The 8 km long elevated system uses Bombardier’s Innovia APM 100 technology, is fully-automated and has 100 person vehicles spaced at roughly 5 minute headways.

It’s clearly an Automated People Mover or Automated Guideway Transit system. But given that I’ve already ranted and raved about nomenclature issues enough already, I’ll save that topic for another time.

The system itself has been plagued by problems and is in danger of becoming a legendary transit white elephant. But what really caught my eye were those windows:

Before. . .

. . . and after.

As you can see in the short video below, the windows are equipped with smart glass technologies. This allows the windows to switch instantaneously between opaque and transparent modes:

This has certain clear (sorry) advantages. The BPLRT travels through high density, residential highrise neighbourhoods. As the system is elevated, concerns exist for those apartment dwellers whose privacy could be compromised by riders of the BPLRT. The smart glass idea solves that problem . . . sort of.

The strange thing is that while the sides of the vehicles are smart glass equipped, the front and rear windows of the vehicles are not. You can still see into apartments from these areas. Given that the front and rear areas are such prime seating areas, I suspect some people’s privacy will be compromised by curious eight year olds peeping into whatever apartments they can.

Spiderman knows what you wear to sleep at night.

I also think there’s a kind of Ostrich Effect going on here. Let me explain:

The story goes that ostriches hide their head in the sand to avoid predators. Because the ostrich cannot see it’s predators, the ostrich assumes it is safe from its predator. Hilarity and nature channel violence ensues. The story is obviously pure myth but endures as a fantastic metaphor for the consequences of the ignorance that arises from only viewing the world from your own, first person vantage point.

Isn’t the BPLRT acting in the same way?

Sure riders cannot see into the apartments, but apartment dwellers can still see the vehicles. Even if you can’t see the riders, it’s still a little disconcerting, no? I’m not sure this actually alleviates the concerns of apartment dwellers. But at the same time, I don’t know. I’m torn on this one and would love to hear what Gondola Project readers have to say about this issue.

Nevertheless, it’s an innovative technique that is remarkably rare in the world. I can’t think of any transit system that’s ever employed the idea. But then again, I didn’t know about the BPLRT until three days ago. As I’ve said before, you don’t know what you don’t know.

Whether it works as planned or not isn’t the point. At least Singapore’s transit agencies are trying things. They’re thinking, experimenting and challenging established norms. They should be congratulated for that.

As for how this applies to gondolas and cable cars . . . I’ll leave that to the commenters. I’m sure Gondola Project readers will have fun arguing and discussing that one for a long time to come.

Note: Travel, ridiculous time zone changes and conference lectures have meant I’m behind on my posts (again). Really very sorry and I’m trying to catch up. Please, stay tuned.

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.

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.


  1. Smart glass makes a lot of sense to me however, it can get a bit pricey for an entire system. Another way of handling certain situations such as the Burnaby Mountain project where the gondolas will look down into a few backyards but not into high rises would be gradiated fresnel lenses. This would have the advantage of horizontal viewing but as the person looks down the window would be obscured. This however would not be able to be switched on and off.
  2. I know of houses using that technology to "shut down" when privacy is needed but again if you are living in the heart of the city or at least near to one of its necessary arteries you should know about those forms of transportation. Rarely: On the other hand exhibitionists could use it in their favour. Clearly: It is a mentionable option for solving that problem. But shouldn't cars and buses get the same technology then? Optional: I know of places in front of windows where you are not able to look straight but up or down - enforced by a special angle of shutters. But you still can see something. Arabic: I further know of places in the arabian world, where next to a traditional single family house a big hotel opened. So the owner of that house covered his ground by a big roof to avoid possible looks of the people in the hotel towards his house and family (only caused by following the religious rules). So who can you blame? Indeed: it is a difficult topic. I'd say it always depends on the situation whether it is necessary to install such measures or whether not. Very similar to the google-street-car debate about blurry houses and/or not.
  3. @ LX, "Optional: I know of places in front of windows where you are not able to look straight but up or down – enforced by a special angle of shutters. But you still can see something." Gradiated fresnel lenses basically do the same except they can be put on the window as a film instead of either sandwiching shutters or building it into the glass.
  4. Smart glass could have an interesting selling point. Ads could be projected on them while opaque. If the privacy issue was the last thing stopping urban gondolas from taking hold I could live without any windows.
  5. Going without windows would be a bad idea, and not just because the views are one of the best things about elevated transit. The people in the gondola do not want privacy. People can be uncomfortable trapped in a small space with a small number of strangers, and windows help with that. It's why many malls use glass elevators. Women especially tend to be more comfortable with them. Sure, cctv should be used for security, but there is a psychological component to feeling secure, and windows really help by making it easy to see and be seen and they make the space feel less claustrophobic.
  6. @Eric, As a claustrophobic I agree 100%. I was just trying to say that if the privacy issue were the only issue keeping cities from installing them, do whatever it takes.
  7. why not put the smart glass on the houses? then riders can't see in and residents can't see the cars. maybe you could make it become an image, instead of just frosted, and people could customize them. like wallpaper on your computer. they could turn into "nature scenes" or "curtains". or if you didn't care, just turn the smart-part off.
  8. @Rose: aren't those called drapes? ;) About those infrastuctural installations: I believe there will be always someone who will be against it. In case of the Roosevelt Island Tramway I'd say people are happy about its existence, same for the Chicago Loop and the Wuppertal Schwebebahn. Why? Because it seems like all those installations have always been there. Which probably means for the Bukit Panjang LRT, in 10 years when the smart glass is getting old and maybe some won't work anymore, glass is what will remain - and by then nobody cares if the windows are opaque or not.
  9. @Rose People consider their back yard or patio an extension of the house. If my wife & I were sunbathing or skinny dipping in our pool, we would be visible from the gondola. This is why we have fences. Also if the gondolas were spaced every 30 seconds your windows would blink all day long. Smart glass is pricey so the onus should not be up to the house owner to install it.
  10. @ sean well lucky you! i have a half dozen apartment buildings circling around my backyard so no skinny dipping in the kiddy pool for me, w or w/o gondola. no one wants a yard surrounded by a 4 story fence... but also, i meant more for systems going past condos and high rises, not fancy suburban homes. as per the video. in which case the glass could be built when the building is built or something. maybe there will be a cheaper innovation way to do this. or everyone can start using one way glass. although that probably works against sun light too. nevermind. @ LX maybe more of a slight fade in and out, with manual controls so you could set it to : on/off/automatic ... i was just trying to get to the idea of residents not seeing cabins instead of riders not seeing living rooms.
  11. Rose, I was just kidding. But I think it is not about the "not seeing cabins" thing, it is about knowing the cabins. The riders actually don't care what you are doing there and with whom.
  12. Hi can you send thru my email how much per panel if there is a prefabricated size or if none, how much would it be for a 1200 x 2400 mm panel?
  13. I have no idea whatsoever. Sorry.
  14. this is amazing -
  15. I first visited Singapore in 1992. The LRT(s) then in place already had these "smart" windows in place. There are now more of them than back then. Living in sunny, HOT Arizona, USA, my first thought on encountering these systems was that these windows were installed to prevent high levels of harmful and uncomfortable UV light (a common problem in AZ, and also a very real problem in Singapore; got a very bad sunburn with what I considered a short exposure time; approx. 1 hour at an outdoor swimming pool). On speaking with local residents, they seemed to support this initial supposition of mine. No mention of use of these windows to address privacy issues ever came up. I am now writing this from Singapore, February of 2013. Some of the older lines had some windows that showed a small amount of deterioration at the edge of the windows; one had a strip approx. 10 inches high, located at the top of the window that did not function as a "smart" window. Another transport unit had one or two of the windows that should have been of the smart variety that were not functional. My conclusion is that this functionality is probably achieved with some sort of window film, and is not a function of the glass itself. I am currently researching this out of curiosity, but do not yet know the manufacturer of the product nor precisely what technology is used. I do believe that what I am sharing here can address some issues brought up in the previous postings as well as clear up some misconceptions and/or lack of information. If I am successful in determining the technology used and/or the manufacturer & cost of this technology, I will also share this information. Thank You all for your opinions and information.
  16. Have just been made aware that the year (1992) that I mentioned in my previous posting is most certainly an error (faulty memory) on my part. However, I do know that I first saw these windows very early in their existence, as they apparently were first installed around 1999. This would correspond with one of my other trips to Singapore; I have made several trips to Singapore, and 1992 was my first. It did not require much time or effort to discover my error. I am now quite certain that I saw the systems in question during a later visit. Thanks again for all opinions and information that have been shared in this forum.
  17. please i wold like your help to made new cable car in my country [Green mountain] in libya. if your company don't mind email me as soon as possible phone number [00218923907353] the cable car to be between two mountains 2.4 please i wold like your help to made new cable car in my country [Green mountain] in libya. if your company don't mind email me as soon as possible
  18. Please contact us at info@creativeurbanprojects.com and we can discuss further.

Leave a comment

You can add images to your comment by clicking here.