staging post 
noun
A place at which people, vehicles, or aircraft regularly stop when making a particular journey: the island was used by the company as a staging post for its ships figurative a staging post in the sport’s history...
- It's very wild country and after nearly one hundred kilometres of this, the track arrives at Gangotri, the last staging post on the journey.
- Britain was then mainly interested in the area as a staging post on routes to its empire further east.
- Its 3,000 ft volcanic peaks make it unsuitable for agriculture or industry, but Britain colonised it almost 350 years ago as a staging post for shipping.