The simple, but mind-bogglingly persistent problem with Melbourne’s new trains

Update 11/12/21: A lot of what I wrote here I have discovered in time to be incorrect–primarily that the buttons aren’t touch sensitive, but rather pressure sensitive. The timeout/lockout behavior seems to have been altered.

Have you been on one of Melbourne’s new High Capacity Metro Trains (HCMTs) yet? They’re very nice–long, plenty of comfy seats as-well as standing area, and modern passenger information with dynamic line maps, all as you’d expect from a modern metropolitan/suburban train system. It’s checkmarks all the way down, except for one problem. Sometimes the doors don’t open.

The fault seems to manifest due to three main properties that I’ve observed of the new door buttons.

• The buttons are touch-sensitive, meaning simply resting your hand on the button is enough to trigger it.
• However, there are no obvious indications that this is the case, with the button formed in a rubbery convex shape.
• If the button is triggered (read; someone is touching it at any pressure) whilst the doors aren’t yet unlocked, the doors will not open, even if the doors later get unlocked. The button has to be released completely, all hands off, and then triggered (touched) again.

Passengers attempting to alight the train seem to have one of two main reactions when the doors fail to open. Some will remove their hand completely from the button, causing the button to unlock, then apply their hand to the button again, successfully opening the door. A sizeable percentage of customers however (I estimate at 30%,) will not fully remove their hand from the button, but rather ease up pressure whilst still contacting the button, before attempting to press harder again. I understand why one would do this–it’s what works on all the trains in the state as they feature regular tactile buttons. However, these aren’t tactile buttons, they don’t click, and merely touching the button is enough to trigger it. In the instance where a customer is continuously touching the button before the driver unlocks the doors, the doors will not open, even if the driver unlocks them manually. The buttons engage a kind of ‘lock-out’ behaviour until all hands are off the button.

Whilst there is signage stating that you must wait for the buttons to show green before pressing, indicating the doors are unlocked, passengers do not read these. And why should they? Every other train in the state (with door buttons) functions in the exact same way; holding the button before the doors have been unlocked doesn’t “lock out” the door until the button is released, instead, the doors simply open when allowed by the driver.

This problem was present on the very first passenger run back in December last year, and I spotted it again twice today. It seems like it’d be a simple fix, with the fault residing entirely within the controller logic that drives the door buttons, but this is just myself making assumptions. Whatever the cause, I hope this problem is being given the attention it deserves by Metro. As more and more of these trains come into service, more and more passengers will be triggering the issue. And typically when a passenger realises that their door isn’t opening, they panic, running to a door that did successfully open–this isn’t very safe.

In other aspects, the train is perfect. They seem mechanically reliable. There is plenty of space to sit, and more space to stand if required. The new passenger information displays and announcements are clear and more informative than previous models. Overall, the future looks bright, the bugs just have to be squashed first.