How to use the online alarm clock
While you wait to take over the metro control-room shift, set the alarm for 12:56 am and keep the current time visible. The four minutes before 1:00 am leave a short, clear window to check the handover notes without losing track of the appointed moment. Keep any workplace clock in view as a second reference.
Your handover may stay quiet even when the alarm fires if its sound has been routed to headphones without you noticing. Check the audio output shown by the computer, then make a brief test sound at a suitable volume before settling back to watch the clock. Do not rely on this browser alarm as the sole cue for the metro shift: if the browser is no longer running or the computer has gone to sleep, it will not sound.
Waiting under control-room lighting near 1:00 am can make a bright clock display unnecessarily harsh. Reduce the screen brightness enough to read 12:56 am comfortably, use the room’s available background lighting, and place the display slightly farther away rather than staring at it continuously. A quick glance between handover checks keeps the time readable while giving your eyes regular breaks from the screen.
Common questions
Can I change the sound?
Yes, there is a short list of tones to pick from before you press Start. Softer sounds are easy to sleep through, so a firmer bell tends to be the safer choice for anything early in the morning.
Will it still be right when the clocks change?
Yes. It reads your device's local clock, so the move between GMT and BST at the end of March and October is picked up automatically, as long as the computer's date, time and time zone are set correctly.
Can I use this on a phone?
It works in a mobile browser, but phones lock the screen and suspend background tabs far more readily than a laptop does, which can stop the alarm sounding. For anything important, a desktop or a plugged-in laptop is the steadier option.
Does the alarm still work if I close the tab?
No. Everything runs inside this page, so closing the tab — or quitting the browser altogether — ends the countdown there and then. Leaving it open in the background is all it asks, and switching to another tab makes no difference.
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