Trains home fill up in a fairly predictable order, and being on the platform a few minutes earlier changes the journey considerably. This page tracks the exact time left until 5:06 pm, whether that is the train itself, the walk to the station, or the point work has to stop for either to happen.
The count makes no sound and asks for no attention while it runs. It is a number, not an alarm, and nothing goes off when it reaches zero. Leaving the page open in a background tab is perfectly fine — it will carry on counting towards 5:06 pm whether or not anyone is watching it.
British speech has a well-worn habit of dropping the middle out of a time: half seven means half an hour after seven, never half an hour before it. Quarter past and quarter to work the same way. Written down, the same moment appears plainly as 5:06 pm, or as 17:06 where no ambiguity is allowed.
Common questions
Does the number update by itself?
Yes. It recalculates every second from your device's clock, so there is nothing to refresh or restart. Whatever is on screen is the current gap to the target time, not a figure worked out when the page first loaded.
What happens if 5:06 pm has already gone for today?
The count simply carries on towards the next occurrence, which is tomorrow. That rollover happens on its own — the page does not need reloading and there is nothing to reset by hand.
Which clock does it use?
Your own. It reads the local time and time zone from the device you are looking at, so the figure reflects where you actually are rather than a fixed zone written into the page.
Will this alert me when the time arrives?
No. It is a live number rather than an alarm — nothing rings, buzzes or notifies you at zero. If you need to be interrupted at 5:06 pm, set an alarm as well and treat this page as the running total.