NS ticket vending machines from left to right: the old zip-code based machine, left photo features the newer touch-screen models(newest model on the left, older model on the right).
[right picture taken from wikipedia]

design for walk-up-and-use
Designing good interfaces for the public domain is probably one of the hardest tasks there is. You need to cope with 'walk up and use'. People that don't know the product have to be able to use it right away. When considering a ticket vending machine for the railways you need to add to that an extremely diverse target group (from kids to seniors, from businessmen to the disabled). And everyone's in a hurry at the ticket machine, so you get nervous, feel rushed. Not a very comfortable situation. Imagine yourself having to use this machine.

touch-screen design
So it's a tough situation to design for. And now it's time for a compliment. The Dutch Railways (NS) have been working on improving their ticket vending machines for the last years. Granted, this was probably sparked by their ambition to have every passenger buy their tickets at the vending machines instead of at a desk, because of reduced cost. They started out with a machine where you had to punch the zip-code of your destination, which had to be selected from along list. This is a touch task if you're unfamiliar with your destination rushed. A few years ago they introduced a machine featuring a touch-screen, that guides you through the buying process (presentation on the ticket machine at the Dutch sigchi chapter, in Dutch only). Recently they've updated the touch screen model, which I used several times now. And I must say, I'm impressed.



It's become much easier for example to buy multiple or complex tickets (say from Delft to Utrecht over Grongingen), undo steps, choose your method of payment. Try for yourself at the interactive demo of the interface the NS provide on their website. Still, most people will not feel really comfortable when buying a ticket, but I think the NS are doing their part to make it as usable as possible. And you might say I'm biased, considering the fact that I'm Dutch, but here's a second opinion about the machine from someone from abroad.

UPDATE
An update (improvement) of the user interface of the ticket vending machines led to a lot of confusion among train travellers for a few days. Read more here.

More uselog posts on ticket vending machines
> Users fix ticket machine interface themselves
> Please do not hump the vending machine
> Unclear labeling: parking ticket machine UI
> Possibilities of RFID Daze Designer of Card-Charge Machine