Cablevision Systems Corp. (CVC), Verizon Communications Inc. (VZ), AT&T Corp. (T), Sprint Nextel Corp. (S) and more than a dozen other firms have submitted competing proposals to provide wireless broadband service to customers on New York City commuter trains.

The proposals set the stage for a battle over a key prize in the war for Internet subscribers in the New York metropolitan area. They were submitted for rail lines serving about three-quarters of a million people from some of the most affluent neighborhoods in the nation who ride the commuter trains for an average 45 minutes to an hour each day.

New York's Metropolitan Transportation Authority (MTA) said Wednesday it received the proposals after it sent out requests gauging interest in the project in July. The respondents seek to provide the service on Metro North train lines to upstate New York and Connecticut as well as the Long Island Railroad, the two busiest commuter rail lines in the U.S.

Cablevision, whose footprint encompasses much of the attractive tri-state market, launched a Wi-Fi network one year ago that's already available at roughly 96% of commuter rail platforms and station parking lots serving Long Island, Connecticut and Westchester County. The company said it's proposing to shoulder all the construction and operational cost of the undertaking for the cash-strapped MTA, making the service available to its existing broadband subscribers at no additional cost and other commuters on a subscription basis.

AT&T expressed interest in the project, but noted that the process was still early, according to a spokesman. The company has talked with the MTA about its experience with Wi-Fi, including offering access points for free to its smartphone users.

Verizon, Sprint and AT&T couldn't be reached for comment.

MTA spokesman Aaron Donovan said this was the beginning of a procurement effort that would likely end in an open bidding process. The MTA recently awarded Transit Wireless LLC with a contract to provide underground cellphone service in New York City subway stations.

Kevin Curran, senior vice president of wireless product development with Cablevision, said its proposal could provide the MTA with new revenue opportunities at no cost, and it would give the MTA control over part of the bandwidth of the network in order to monitor trains, electronic ticketing and other services.

Curran said that about half of the Metro North and Long Island Railroad riders are already Cablevision customers. "We've been in this business now for a year, and the response from our customers is overwhelming," said Curran. "They want broadband access on the trains."

If Cablevision is successful in its bid to provide the service, it could bolster its standing with customers in the tri-state area as it loses subscribers to new competition, such as the Fios TV service launched in Cablevision's territory and elsewhere by Verizon. Phone companies that have entered the pay-TV and broadband Internet service business have a leg up on their cable counterparts in the wireless area, thanks to their existing wireless networks.

Unlike cellular wireless networks, Wi-Fi has traditionally been used to serve stationary users within a given coverage area, so Cablevision would face additional costs in providing service to passengers on moving trains. On the plus side, many devices are made to be Wi-Fi-enabled, so they don't require any additional accessories.

"It doesn't sound terribly expensive for Cablevision to build it, and it makes sense for them given their coverage area and the new competition they're facing," said UBS analyst John Hodulik.

Skeptics say Wi-Fi will soon be eclipsed by new, faster and more mobile wireless networks using fourth-generation, or 4G, technology such as WiMax or LTE. The nation's largest cable operator, Comcast Corp. (CMCSA) offers WiMax service in Portland, Ore., Atlanta and Bellingham, Wash., and it expects to expand the service to Philadelphia and Chicago by the end of this year. Time Warner Cable Inc. (TWC) expects to offer WiMax service in Dallas and three cities in North Carolina later this year.

Neither Comcast or Time Warner Cable submitted proposals to the MTA, since the commuter trains are not in their footprints.

- By Nat Worden, Dow Jones Newswires; 212-416-2472; nat.worden@dowjones.com

(Roger Cheng and Tess Stynes contributed to this story)