Have you ever encountered two or more productions that are close to each other, but not close enough to cover them with one station? That's why you need to learn about beaming.

Lets imagine you placed a station, but it doesn't reach the Coal Mine like on screenshot below.
Simply place a single tile station near the Coal Mine while holding a Ctrl button.
Choose station you wanted to expand. Now your trains can successfully grab the coal.
This trick works with any type of stations. It could be dock, airport or a bus stop.

Note that beaming may be disabled on some servers by setting or by the rules. So do not abuse it, use only when it's necessary. Like when someone blocked the production or to avoid ugly station placement.