Why doesn't the industry use my line?

If I understand the question correctly, you're planning to just dump the stone somewhere? That's not going to work. You can force unload the stone at a station and transport the last bit by truck, though.

The game does these things automatically after some time (one in-game month roughly). All your stations that are connected form a network and the game ensures that goods travel across it. You don't need to manually tell vehicles to dump goods at mid-points (like in old Transport Tycoon), the vehicles understand this and even sometimes pick alternative routes, if several are available.

You must however ensure the following:

• Station 1 is connected to the quarry. Looks ok from the screenshot.
• Station 2 is close enough to a truck station, with road between them.
• There's a train going on a line between the stations, with correct wagon types.
• There's a second truck station near the resource consumer, such as the construction materials plant, again with road between the station and the plant entrance.
• The produced goods by the plant are transported to another consumer.

Just as in the real world, stone is transported with trucks, not by bus. So obviously a bus line will do no good here, except for transporting stray workers to the plant (you won't get rich from that).

The quarry won't produce stone if you don't pick it up, but it also won't produce stone if there is no demand for it. The construction material plant only has a demand for stone, if there is a demand in turn for construction materials (view "potential" in the details tab of the plant's info window). And so on - in the end you'll have the consumers in a town.

When planning a new line, always start on the consumer side. Who will use the end product? And can you afford to build the whole supply chain needed?