Complex sentence: Another renovation of the station is planned within the next several years, but because of its unusual design, it may never be made more efficient--riders may continue to have to go downstairs and then back up to transit the station.
Split into simpler sentences: Another renovation of the station is planned within the next several years, but because of its unusual design, it may never be made more efficient. Riders may continue to have to go downstairs and then back up to transit the station.