Answer: The connective used in the example provided shows a time relationship.
Explanation: A connective is a word or a phrase used to connect two or more ideas and to establish a logical relationship between them. Some of the relationships that connective can show are time, space, result and contrast. In the case of the sentences "The train was late. Soon it came rushing down the track", the connective is "soon". "Soon" establishes a time relationship because it connects the second idea to the first one by indicating that the event presented in the second sentence took place after what was expressed in the first one. In other words, the connective "soon" places these events in a timeline.