Martin Depot The former Southern Railway depot at Martin was built around 1875. Renovated for business use in the 60s or 70s, it is now occupied by Mountain Air, a local heating and air conditioning company. The tracks are still used by the Hartwell Railroad. Martin, a town of 310 people, is located in southern Stephens County near Lake Hartwell.   Georgia's Railroad History & Heritage. Copyright, Steve Storey. Railroad History | The Depot List | Locomotives On Display | Odds & Ends | Sources & References | Home