Sometimes the design of a user interface says volumes about the people who made it.

I’ve been spending some time recently scrutinizing the various door-operation buttons on Norwegian trains. Bear with me.

The photo below shows the buttons from an older style of train car. The red button on top opens the door and the black one underneath closes it. Both buttons are labeled, in both English and Norwegian.

Why red to open the door? And why black to close it? It seems a strange choice of colors for ‘Open’ and ‘Close’, unless you know a little about electrical engineering: the convention is that electric wires are colored red for positive wire and black for negative. (Note: This is the exact opposite of accounting, where red numbers are negative and black numbers are positive.)

Why not use red and green instead? Well, part of the reason is that about 1 in 8 adult males are colorblind. So, if you color the wires red and green, about 1 in 8 electrical engineers will eventually electrocute themselves.

It seems odd to me that in order to make the doors open so that I can leave the train, I would need to push a red button. From traffic lights, I’d be inclined to look for a green button to make the doors open and a red one to make them close.

So, I am guessing that the guy who picked the button colors was the electrical engineer who designed the system. That is, he chose the colors to make it easiest for himself and other electrical engineers to build and maintain, not easiest for travellers to use (even though travellers probably push those buttons thousands of times more often than maintenance personnel).

Really the only way to tell which button does what here is to simply read the label. If the labels fell off, there would be no way to know which button did what except by pushing them and watching what happened. I’ll bet that someone somewhere along the way received enough complaints about how confusing for passengers it is to have the buttons be red and black that they decided to revise the panel.

Below are the buttons from a newer style of train where they’ve ‘fixed’ the color scheme. Now it is green for open and red for close. Except, they seem to have made a new mistake. Colorblind people cannot see the difference between a red traffic light and a green one, so they differentiate them from their position. In many places in the world (Norway included), traffic lights are positioned with the red light on top and the green light at bottom. (Some places orient the lights in a row from left to right, with red on the far left and green on the far right, but in Norway it’s red on top and green on bottom.)

For these buttons, though, the positions are reversed. The green button is on top and the red one on the bottom. So, if you are colorblind and don’t speak either Norwegian or English, you might push the red button over and over again at your stop, thinking you were pushing the green one.

A transparent ring surrounding each button helps avoid this by lighting up when the train is stopped, but in good lighting it can be tough to see which button, if either, is lit up.

They still have the labels, though, so now you have three ways to tell which button is which: read the label, look at the color of the button, or see which button is illuminated.

Perhaps the designers realized the downside of having the green button on top and red on bottom because the Type 76B train cars have revised the layout once again.

In this kind of car, the buttons are placed side-by-side, with red on the left and green on the right (just as it is with some kinds of traffic lights). The buttons are labeled, like elevator doors with ‘><‘ for Close and ‘<>’ for Open. And, to top it all off, the buttons light up from within (although I did not manage to get a photo with the buttons lit up. Even in very-polite Norway, people can have exceedingly little tolerance during peak travel hours for amateur photography of their public transit systems).

So on this kind of panel, the designers have actually built in 5 separate ways to determine which button does what: (1) the plain language labels under the buttons, (2) the text characters on the buttons themselves, (3) the relative position of the buttons, (4) the color of the buttons, and (5) the presence or absence of internal illumination.

The only things I can think of that they could realistically have done, but have not, are make the buttons different sizes or shapes.

Here’s the thing, though, that the designers of these systems never quite seemed to figure out: Nobody ever uses the ‘Close’ button. When you get off a train, you open the door and depart, leaving the door open behind you. When you get on a train, the last person on does not close the door, since he isn’t certain that he’s the last person on. He doesn’t need to close the door anyway: The train personnel have a switch that closes all of the doors immediately before the train takes off. They even announce over the intercom system right before closing all of the doors, so that no one gets caught in a doorway.

So, the latest style of control panel, from the Type 69C trains, only has one button, the only button anyone ever needs: Open. It is labelled with text in both Norwegian and English, it’s colored green and also the lights blink when the button is active, but all of this is really superfluous, since there’s only one button and it only does one thing. There’s no need at all for the label, the green color, or the blinking lights.

In fact, for the oldest trains that are still in use, the doors do not open electrically. You must swing them open by hand (though again, the train personnel close them all mechanically before the train takes off). For those trains, the door does not have any buttons to push – it simply has a handle you turn. It might be difficult to believe, but the handle does not light up, it does not blink, and it is not even labelled. It is just a single metal handle on a swinging door, and the passengers are expected to figure out how this mysterious device works entirely on their own.


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