By Janet Roberts

NEW YORK (Reuters) - Almost 200,000 suburban New York City commuters, most in New Jersey, face another work week without easy rail connections because of storm damage so severe that experts say it will take months before full service can be restored.

Hurricane Sandy severed train connections for an estimated 435,000 daily commuters in the New York City suburbs. By Monday morning, full or partial service will have been restored for about 260,000.

Experts with experience repairing rail after other natural disasters say commuters on some of the most damaged lines are likely to face a long wait. Some suburban residents may be able to travel by bus as an alternative.

"Getting the system back to normal, where every train is operating as it was before the storm, I could easily see it being months," said Conrad Ruppert, associate director of research at the University of Illinois Rail Transportation and Engineering Center.

"Getting back to operating trains with limitations and restrictions, you're already seeing that now."

Ruppert worked for 35 years for Amtrak on the Northeast Corridor, where he oversaw restoration work similar to those that crews are performing in the region today.

Service on three New Jersey Transit rail lines, one Long Island Rail Road line and the PATH train remains fully or partially suspended because of extensive damage that experts say will require lengthy repairs. Those lines log more than 367,000 passenger boardings on a typical weekday.

New Jersey Transit's rail network transports roughly 46,000 people on 63 trains during a typical weekday morning to New York's Penn Station, but on Monday it will only be able to carry 15,600 on 13 trains, said spokesman John Durso Jr.

"The road to recovery is still long, arduous and continuing," he said.

To offset the drop in rail service, NJTransit is boosting its bus capacity to 115,000, a roughly 28 percent increase.

NJ Transit's heavily used Midtown Direct service - the Morris and Essex and Montclair-Boonton lines, which together carry about 35,000 weekday passengers - is shut down indefinitely because of damage to the Kearny rail junction, which remained under several feet of water on Friday.

Floodwaters washed ballast from beneath the track in this area, damage that will require extensive repairs before service can resume to either New York Penn Station or Hoboken Terminal.

The Midtown Direct lines also have extensive tree damage in the areas around Summit, Morristown and Denville.

"My guys say it's the worst tree damage they've ever seen," said Jeff Reese, president of K.W. Reese Inc., a Mercersburg, Pennsylvania, railroad contractor. "There are huge, 24- and 36-inch trees lying across the train tracks or lying across the catenary lines that power the trains.

"The foreman says they don't know when they're going to be done. I think they're going to be there for at least a total of a week."

Also heavily damaged was the southern section of the North Jersey Coast Line, from Bay Head to Woodbridge. The storm surge sent two boats, a shipping container and other debris crashing onto the Morgan drawbridge at South Amboy, and flooding caused extensive rail washouts along miles of track south of there.

Service along the northern part of the line, from Woodbridge to New York Penn Station, has been restored on a reduced schedule.

Further complicating service restoration for NJ Transit is flood damage at Hoboken Terminal, the terminus for Pascack, Main Line, Bergen County and some Morris and Essex trains. Flooding was so severe there, the waiting area had more than 5 feet of standing water. The water washed out tracks and damaged power substations, signals and switches.

The PATH system, which runs through the tunnel at Hoboken and which also saw flooding at its Jersey City station, is grappling with similar damage. New Jersey Governor Chris Christie said at a press conference on Tuesday that he expected repairs to take at least a week to 10 days.

The PATH system sees more than 260,000 passenger boardings on an average weekday and serves as a vital link for commuters between Jersey City, Hoboken and New York.

SIGNS OF LIFE EMERGING

Elsewhere, the region's commuter rail system is coming back to life, albeit on a mostly reduced schedule.

NJ Transit's most-traveled Northeast Corridor, from Trenton to New York Penn Station, had less damage than other lines and resumed a reduced schedule on Friday. Service resumed Sunday on a reduced schedule on the Main Line from Port Jervis, N.Y., to Secaucus and part of the Raritan Valley Line from Raritan to Newark Pennsylvania Station. Normal service resumed on the Atlantic City Line from Atlantic City to Pennsauken.

The Pascack Valley and Bergen lines remain suspended because power remains out in those areas, NJ Transit said. After it is restored, NJ Transit will have to test and repair equipment before service can be restored.

Long Island Rail Road had downed power lines, switch damage, storm debris and flooding throughout the system. Though all but one of its lines have resumed at least partial service, all continue to operate on reduced schedules because of continued flooding in two of Amtrak's four East River tunnels.

MTA recommends passengers travel during off-peak hours when possible, because trains will be crowded during morning and evening rush hours.

The Long Beach Branch, which saw the worst damage, remains out of service. The rail bridge between Oceanside and Island Park needs extensive repairs. The railroad is exploring options for restoring service west of Island Park, said Salvatore Arena, an MTA spokesman.

Ronkonkoma Branch trains are not running east of Ronkonkoma, and the Montauk Branch remains suspended east of Speonk. Repair work continues on those lines.

Metro-North was operating all three of its East of Hudson main lines on a reduced schedule on Friday and began full service on Saturday. Branch line service from Waterbury, Danbury and Wassaic will resume Monday morning. Repairs continue on the New Canaan Branch, where fallen trees severely damaged overhead wires. Buses will run along that line, connecting to main line trains.

(Additional reporting by Ernest Scheyder; Editing By Dan Burns, Cynthia Osterman and Ken Wills)