8/16/2009

How much it costs for a screen door?

A $126m contract to instal screen doors for 36 MRT stations was awarded to ST Electronics and this has resulted in several discussions in cyberspace, all trying to guess how much is the cost of a screen door. The numbers vary from $60k to $100k per door. Let me try another guess. Each train has 6 cars with 2 doors each on either side, and only one side of the doors will be in operation at the station. And with 36 stations with one platform each with two sides, the number of screen doors should be 6 x 2 x 36 x 2 = 864. This works out to be $145.8k per door. If we add 2 more platforms for the interchanges at Jurong East and Tanah Merah, assuming each has 2 platforms instead of 1, then the additional number of platforms shall be 48, giving a grand total of 912. The cost of each screen door shall be $138k. Now, I think I am right on this number and any variation will be due to stations with more than one platform that are not accounted for and can be adjusted accordingly. So at $138k per screen door, this amount could actually buy a Mercedes Benz or a new 3 rm HDB flat in the new towns. In other words the $126m can buy 912 Mercedes Benz or 912 3rm HDB flats. The screen doors are indeed a little costly right? Correction. There are 24 doors on each side of a train instead of 12 doors as computed above. 4 per car instead of 2. Thus the cost per screen door should be halved, ie $69k. This is close to the actual number given by LTA at $65,600.

6 comments:

Anonymous said...

Out of 36 stations, 33 stations have 2 platforms each and 2 stations have 4 platforms each and Jurong East Station after expansion will have probably 6 platforms.

So total count for platform doors should be (24 * 33 * 2) + (24 * 2 * 4) + (24 * 6).

Plus the cost also includes installation costs and the costs of the glass screens running the entire length of platforms so I would say that these account for a large proportion of the high price tag too.

But I won't deny that even after accounting for all this the price could still be too high (just not as extreme as originally thought), and we won't know what's causing it unless a breakdown is given, which obviously won't be provided. :)

redbean said...

altogher 36 stations. 34 have 1 platform with 2 sides, thus 24 doors for one station. tanah merah has 2 platforms, thus 48 doors. or maybe 36 if i am not mistaken as one platform operating only on one side. let's take it as both sides operating. jurong east has 6, if these are factor in, total 144 doors. i think you meant 3 platforms as currently it has the equivalent of 2 platforms with 4 sides operating. thus it will mean 72 doors.

34*24 + 2*24 + 3*24 = 936

your number is 1920 as you double the doors per station. each side of a station has 12 doors. 2 sides = 24 doors.

my original number was 912 doors, without the additional 2 platforms.

at 936 doors, still works out to $134K per screen door, ie door plus screen.

Jaunty Jabber said...

Redbean, what you have just done is fascinating, calculate the cost of each screen door. And Wow, the number is outrageous.

After this initial price to pay for each door, there are maintenance cost to pay as well.

redbean said...

shit, my numbers were wrong. there should be 4 doors per car instead of 2. so the cost of $138k should be halved, ie $69k per screen door which is near to the LTA number of $65.6K.

Anonymous said...

Those glass screens and doors are all potential advertisement space. More numbers of effective eyes balls than internet and newspapers. They should make money. The cost has to be high so that the profit margin is low i.e the commuters will not be able to claim for fare reductions.

redbean said...

you got your point there. let's hope they won't charge it all to cost and use it to justify for higher fare.