to Seward and gravel from the Matanuska Valley to Anchorage. It is well known for its summertime tour passenger service. The Alaska Railroad was one of the last railroads in North America to use cabooses in regular service and still uses them on some gravel trains. It continues to offer one of the last flag stop routes in the country. A stretch of about of track along an area north of Talkeetna remains inaccessible by road; the railroad provides the only transportation to rural homes and cabins in the area. Until construction of the Parks Highway in the 1970s, the railroad provided the only land access to most of the region along its entire route. In northern Southeast Alaska, the White Pass and Yukon Route also partly runs through the state from Skagway northwards into Canada (British Columbia and Yukon Territory), crossing the border at White Pass Summit. This line is now mainly used by tourists, often arriving by cruise liner at Skagway. It was featured in the 1983 BBC television series Great Little Railways. The Alaska Rail network is not connected to Outside. (The nearest link to the North American railway network is the northwest terminus of the Canadian National Railway at Prince Rupert, British Columbia, several hundred miles to the southeast.) In 2000, the U.S. Congress authorized $6 million to study the feasibility of a rail link between Alaska, Canada, and the lower 48. Some private companies provides car float service between Whittier and Seattle. Marine transport Many cities, towns and villages in the state do not have road or highway access; the only modes of access involve travel by air, river, or the sea. Alaska's well-developed state-owned ferry system (known as the Alaska Marine Highway) serves the cities of southeast, the Gulf Coast and the Alaska Peninsula. The ferries transport vehicles as well as passengers. The system also operates a ferry service from Bellingham, Washington and Prince Rupert, British Columbia, in Canada through the Inside Passage to Skagway. The Inter-Island Ferry Authority also serves as an important marine link for many communities in the Prince of Wales Island region of Southeast and works in concert with the Alaska Marine Highway. In recent years, cruise lines have created a summertime tourism market, mainly connecting the Pacific Northwest to Southeast Alaska and, to a lesser degree, towns along Alaska's gulf coast. The population of Ketchikan for example fluctuates dramatically