What is the fine-grained topic of the following text: The Northern Extension of the Crenshaw/LAX line would bring the light rail line north thorugh Mid City, West Hollywood, and Hollywood to the Metro Redline, resulting in between 5-9 new stations and 6.5-9.5 miles of new track, depending on which alignment alternative is selected. Only return the topic.
Northern Extension of the Crenshaw/LAX rail line