1.
A ~ railway is a major railway between two important places.
...the first ~ railway to be built in Britain for almost a hundred years...
...London’s ~ stations.
ADJ: ADJ n
2.
You can use ~ to describe people, ideas, and activities that belong to the most central, conventional, and normal part of a tradition, institution, or business.
We observe a striking shift away from a labor theory among all ~ economists...
= mainstream
ADJ: ADJ n