Summary
Confused by the elevator system at 388? What does “serving other deck” mean anyway? Why can’t I get there from here? This quick guide will help you master the quirky elevators and impress your colleagues with elevator tricks and facts. (For the record, this was written at home, not on company time. No TARP money was expended for this project.)
Introduction
The elevator system at 388 Greenwich St. uses an unusual (but not unique) design that pairs two elevator cars, one above the other, in every main elevator shaft. These cars are joined together, and move up and down in the shafts together. When at the lowest level, the lower car will be at the Lobby level, and the upper car will be on the Mezzanine level. When the lower car stops on the 6th floor, for example, the upper car will be at the 7th, although the doors won’t necessarily be open. (For a more technical explanation, see http://www.elevator-world.com/magazine/archive01/9807-001.html-ssi)
At least two other structures in NYC use a similar system – one is at Citigroup Center at 53rd and Lexington, and the other (according to Wikipedia) is in the Statue of Liberty. Wikipedia’s entry on double-decker elevators provides a list of examples, and every continent except Antarctica has at least one. It also mentions that the American International (AIG) building in downtown Manhattan was built with double decker elevators, but they were later removed due to their unpopularity.
The usual reason (the only reason?) to use double-decker elevators is to provide elevator capacity without using as much “core” space in the building. During peak load times, twice as many people can be in any particular shaft because of the two cars. Moving that many people simultaneously would otherwise require another elevator shaft. Sometime when you’re on a floor between 4 and 15 in 388, walk around, and notice that office and cubicle space is only available around the outside of a large central core. The core at these levels contains all 3 sets of elevator banks (serving floors 4-15, 15-27, and 27-39) as well as rest rooms, fire escape stairs, electrical and plumbing runs, etc. But the core would be much larger, and the office space smaller, if there were more elevator shafts with single cars. The upper floors of a building have more office space because only the elevators to service those floors are in the core (except for some elevator mechanical space just above the top floor in a particular bank).
The problem with the 388 elevators is that while they may be efficient from a building square footage standpoint, they certainly seem inefficient when you’re riding in them. Unfortunately, the efficiency for the building can be quantified (how many extra square feet are available, what would that cost to build or rent, etc.) but because nobody writes a check for the inefficiency (how much time is wasted by someone traveling in the elevators), nobody really knows the cost of the inefficiency.
This guide will help you understand how the elevators work, and how to make them more efficient for you, though not necessarily for everyone else. In fact, making the elevator more efficient for you makes it less efficient (most of the time) for anyone else on the elevator. But, hey, it’s not your fault that you’re smarter than they are. Once you’ve mastered the elevator shuffle techniques described here, you’ll understand better why the best use of double-decker elevators is for long express runs without intermediate stops. That’s why such towers as the recently-renamed Sears Tower, or the fallen World Trade Towers, use double decker elevators to move twice the number of people to “sky lobbies” but are not used for local runs.
Efficiency at the Lobby/Mezzanine level
Let’s take the example of the so-called low-rise elevators that serve floors up to the 15th. If you get in at the Lobby level, you can select only even floors, and if you get on at the mezzanine level, you can select only odd floors. Ideally, the elevators will make no more than one stop for every even-odd floor pair, like 6th and 7th. The lower will stop at 6 if someone from the Lobby requested it, and the upper would simultaneously open at 7 if a Mezzanine person requested it. This would efficiently move up to twice the capacity of a normal elevator.
Efficiency breaks down once the elevator is underway
The odd-even protocol is not enforced above the starting level. If someone “calls” an UP elevator from the 4th floor, presumably the lower car serving the even floors will make the stop, but the person entering is not restricted to only even floors, and might request 7 for example. If anyone in the upper elevator serving odd floors had also requested 7, both the upper, and then the lower, elevator cars will stop at 7. Since no one on the upper (odd floor) deck would have been able to select 8 (more on this in a minute), the upper elevator will stop on 8 and the doors will remain closed while the lower car (or “deck”) serves the 7th floor. During this time, the confusing (to 388 newbies) “Serving Other Deck” light will illuminate on the upper deck. Now you know what it means.
But the inefficiency goes further. Maybe
you’ve seen (or are) one of those people who want to go to an odd floor but think it’s too much of a bother to go upstairs to the Mezzanine. These people will have to select an even floor at the Lobby, even though they want to go to, say, 11. Most will select 10, and if necessary, get out at 10 and then hit the up button and take a different elevator to 11. Think about this – if no on else on the elevator was going to 10, this action forced one elevator to stop at 10 to allow the perpetrators to exit (slowing everybody else’s trip), then another elevator to stop at 10 so they could reboard, and then to stop at 11. Three stops for one individual! (Now, casual observation reveals that some of these people could actually use a little exercise, so let’s suggest an alternative: take the elevator to 12, and walk down one flight. After getting comfortable with that, maybe take the elevator to 10 and walk up a flight.) And don't even get me started about the people who cross over from 390 at 8, and then take the elevator down 3 flights (instead of taking the stairs) so they can work out at the gym!
It’s fun to watch these people. They’ll press 10, and then as the elevator gets going, and especially when it stops at 4, 6, or 8, they’ll be furiously pressing 11 (or maybe even holding down the button) to see if they can get it to illuminate and stop there. If they’re successful – and we’ll reveal the conditions under which they are in a second – they won’t get off at 10, but since there’s no way to cancel the original command to go to 10, everyone else will have to be delayed as the elevator stops at 10 and no one gets off. Overall, this is better, because only 2 elevator stops were necessary to get these people to their desired floor, instead of three in the scenario above.
When can the odd floor interloper actually get the “even” elevator to stop at 11? One obvious example is if the elevator is called from another floor (like the 4th floor example above). Anyone gettingon at 4 can go to any floor, and since the elevator can’t tell who just got on, anyone in that car can successfully press 11, and the even floor elevator will now also stop at 11. Note that the elevator has to have been called to stop at 4 (say). If someone was just walking by the elevator, and when it opened to discharge passengers decided that this would be a convenient time to go to 7, he/she would be frustrated because 7 would not be selectable if the elevator hadn’tbeen called to 4.
A little known feature is that once the lower deck elevator in that example was called to 4, anyone in the upper “odd floor” deck can also now successfully press any even floor. But, you say, how does the person in the upper elevator know that even floors are now accessible? The “ding” gives it away. When an elevator stops at a floor to let someone out, but no one has called an elevator in the same up or down direction, the doors will open but the bell won’t sound. If you hear the bell, it means that the elevator was called, and any floor can be selected on either deck. So much for efficiency.
Of course, the real crime committed by these odd-even switchers is not that they do it – we’re all trying to maximize our own efficiency – it’s that they do it in a way that makes it blatantly obvious to those they inconvenience. They are essentially saying “My time is worth more than yours” and of course, you don’t agree. This guide will teach you a trick or two shortly that will leave those you inconvenience in the dark about your actions.
Something you need to know
Have you ever entered an open elevator at the Lobby or Mezzanine level, pressed your desired floor, and then waited forever for the elevator to close the doors and begin ascending? Obviously, you got into the wrong elevator, but how do you know which is the right elevator? First, you should obviously head for the elevator with the light on, as that’s the next to go. But, as often as not, that door will close in your face and you might just want to go to the elevator which is next in line. Of the open elevators, the next in line is always the next one in a clockwise direction with the doors open. Pick a different one, and you’ll wait longer. In most buildings, if you get into an open elevator and select a floor, the doors will soon close and you’ll be on your way. Not at 388.
And while we’re on the topic of lights and doors, why is it that the light stays on even as the door is closing? In most every other commercial building in NYC, the light goes off before the doors close. But here, you walk all the way to the last elevator because the light is on just to have the doors slam in your face (with the light still on). Also, here at 388, on the upper floors, the light tends to go on just before the doors start opening. Given how inefficient the elevators are, wouldn’t it be better to signal which elevator is going to open, allowing people to start toward it, rather than waiting until the doors are opening to begin moving toward the now open doors? Building personnel maintain it is for safety reasons. They were afraid of people stampeding the doors and creating injuries. Guess they don’t really view us as the best and the brightest!
Going down, turn a Lobby into a Mezzanine elevator
Let’s say you’re headed down to the Starbucks or the cafeteria on the Mezzanine level, but the elevator that opens up for you is headed for the lobby. Here’s how to change it into a Mezzanine elevator: get on, press L and the button for the floor directly below the floor you’re on, and then get off immediately on the same floor where you started. As soon as the doors close, press “Down” again on the elevator call panel. You’ve just instructed the lower (Lobby) deck to stop at the floor below you, leaving the upper deck to stop at your floor. And since you “called” the elevator, the doors on the upper Mezzanine level deck should open for you, allowing you to go to the Mezzanine without a trip to the Lobby and escalators.
Now, unless you’re really arrogant, you won’t do this if there are people in the Lobby elevator when it opens, but there is still hope. If you get on that Lobby elevator, and anyone has selected an intermediate floor (let’s say you get on at 10 and someone has already selected 5, you can select 6. Get out at 6, and, after the doors close, call a Down elevator. You know that the lower deck is going to 5, leaving the upper deck at 6, and with any luck, the same doors you just exited from should open up and take you to the Mezzanine. And no one on the elevator knows what you did! Of course, if they’re also headed for coffee, and they see you in line in front of them, they might figure it out.
There is a situation in which the above trick will not work. It may be that another elevator is headed to the floor you’re on (say 10) and it will open instead of the one you’ve just left. This happens most frequently early in the morning when many others are arriving.
We get in pretty early on 10, and many people take a Lobby elevator to 10, and often there is no one else in the car or in the car above. As a result, the elevator is set to return to the Lobby, and you’re faced with another Lobby elevator. Of course, you can do the same thing again, with that new Lobby elevator. Unless this happens several times in quick succession, you’ll still get to the Mezzanine earlier. This is especially true if you’re in the mid-rise or high-rise elevators, because of the longer walk to get to the escalators.
Amaze your friends
While some people will need to get on an elevator first before they can determine whether it is going to the Lobby or the Mezzanine, you can do it from the hallway as soon as the doors open. There is one easily visible difference between a Lobby deck and a Mezzanine deck. The pictures below are from the same elevator: one is a Lobby, one is a Mezzanine. Can you spot the difference?
The Mezzanine deck is on the right. Notice that the floor is slightly different, in that there is a square on the floor toward the back. This frame is for an access hatch between the upper and lower cars. If you see the square frame, it’s the upper (Mezzanine) deck.
What other differences are there between Lobby and Mezzanine decks? Look at the pictures below of the button pads from the two different levels of the same elevator.
There’s one obvious difference: on every elevator, the “natural” floors that you can select from the Lobby/Mezzanine level are always on the left of the button pad. So the even floors are on the left on the Lobby elevators, and the odd floors are on the left on the Mezzanine level.
There’s one more obvious difference. Every elevator is labeled with a number followed by a U if it’s the upper deck or an L if it’s the lower deck. See the "4L" in the photo on the right.
What’s the fastest way to get from here to there?
Let’s say you are going from 10 to 27. How should you go? You could take the elevator up to 15, and transfer to the mid rise (15-27) elevators and continue up. Or you could go down to the Mezzanine, and then take the high rise elevator which runs express up to 27. Empirical evidence suggests that the down-up path is faster, especially during the morning when many people are arriving and taking the elevators up. Up elevators will tend to run “local”, stopping on many floors. Even though the distance traveled is shorter, the time is usually longer to go up-up rather than down-up. I’m sure there are similar examples from the other elevator banks.
Stuff you don’t need to know, but might find interesting: 
Chris has an information panel that shows the status of every elevator in the building, as seen below.
Let’s take a closer look.
Pauline Buckley and Kevin Fitzgerald keep the elevators running, both here and in 390. Kevin is shown working on of the cars in the high rise elevators in the picture to the left.Pauline was working in the “pit” below the
The picture below shows the underside of the elevator, as seen from the pit. Notice that it comes to rest above a set of spring loaded pistons which are there for emergency stop purposes. Also notice the yellow (if you’re viewing in color) shock absorber that is apparently designed to prevent the car from shimmying too much as it ascends or descends. The bottom of each elevator car has two of these, one on each side.
Elevator “Parking”
During UPPEAK mode, the elevators are designed to return to the Lobby/Mezzanine to be ready to pick up the next group of “up” travelers. UPPEAK is on most of the time, but there’s also a little used DOWNPEAK mode that lets elevators rest on various upper floors so that “down” travelers don’t have to wait for elevators to reach them from the lowest level.
Is there video surveillance in the elevators?
The short answer is no, but the upper decks (only) were designed for it. Chris Merola told me that as originally envisioned, there was an evening mode for the elevators. Gates came down and prevented access at the Lobby level, so all riders had to go to the Mezzanine. In evening mode, only the first four elevators (two on each side) would operate, and these were the cars fitted with (or at least set up for) the video cameras. But now there are no gates on the Lobby level, evening mode is not used, and there are no video cameras in the elevators.
Final note
Quantitative people generally try to understand the world around them, and that includes how things work the way they do. These elevators are a good example, and discovering the algorithm that dictates the elevator behavior was just natural. But I can understand how some people might say “That guy has too much time on his hands.” Of course I do – I’m standing here with nothing to do while the elevator is “serving other deck”, whatever that means.
