Three Nodes made up the ancient dwarven transportation network. It would effectively stop time for the passengers and send them to their destination, in effect, instantaneously. The three stations for the nodes were dwarven strongholds. Over time, and due to events such as that at Vilhan's Folly, the system was shut down and eventually forgotten.

Node of Space

When activated, flung those around it across the face of Heroshi. Located in 'Ald Fel, behind the gates of Vilhan's Folly.

Node of Time

Created a distortion of time around it. The white dragon Kamro swallowed it and this preserved the dracolich's flesh from rotting. However, the dwarves of the stronghold Val Fel "Stonefast" sealed the dragon in. The node later caused the young silver dragon Tarocalibrant to age rapidly into a great wyrm, and caused him to succumb to Twilight* soon after. The node, which had become Kamro's Phylactry, allowed the dracolich to possess Tarocalibrant's not yet cold body.

Node of Matter

Allowed the transformation of matter. The dwarves used it to create the fortress and tower of Ruhn Muir from solid Orihalcum. This was instrumental in the plans by a duerzagon theurge, a follower of the force of decay. He used an artifact known as the Chaos Gate with the node to invert it immense power, summoning the force of decay itself. 

* Source: Draconomicon. Means dragon death by old age.