Re “An environmentalist makes the case for high-speed rail,” (Viewpoints, Aug. 31): The author of this article is definately not an engineer. In order to reduce vehicle miles by 10 million a day, 15 million passengers a day would have to ride rail, which is physically impossible. The cost of construction would be at least three to four times his estimate. About half of the rail line would require miles of tunnels and acquisition of rights-of-way through urban areas. The line would have to be electrified for its entire length, and supplying renewable energy would prove impossibly expensive. California does not need to construct more new roads, just needs to maintain and improve the existing ones, which can be done at much less cost than constructing this white elephant. Also, travel from San Francisco to Los Angeles is only a fraction of vehicle miles traveled in California. The rail line would also require an operating subsidy of billions a year.