The New Haven Line services the western Connecticut’s need for rail transportation and allowing of commuters to travel from New Haven, CT and New York City (and to all the stops therein)without having to deal with rush hour traffic. It is owned and operated by Metro-North.
The line is actually a group of tracks also used by Amtrak and other rail needs. It is common enough for trains to pass one another, be they Accleas or Expresses. There are also local branch lines. They are as follows: New Canaan Line, Danbury Line, and the Waterbury Line.
The stops along the line are as follows on a southbound trip towards The City. Reverse order is for a northbound trip.
-New Haven, CT
-Green’s Farms, CT
-East Norwalk, CT
-South Norwalk, CT
-Noroton Heights, CT
-Cos Cob, CT
-Port Chester, NY
-New Rochelle, NY
-Harlem 125th Street
-Grand Central Station
Not all of these stations are stopped at during a single trip, and it may be necessary to change trains at either South Norwalk, or Stamford to acquire a local train. For the most part you can catch an express at any major station during regular hours (like not midnight) every half-hour or so.
The power is supplied to the trains by a combination of overhead power lines while in Connecticut, and when the train nears New York City it switches to a third rail system to deal with all the tunnels.
As for the scenery of the line the majority of the line runs along I-95 or within towns. While it does not make for the most naturally pretty ride, it does give you a chance to see towns and cities from a different and quite possibly perspective changing angle. For reasons beyond me shady areas of towns are often near rail tracks.
Riders tend to be business men and women and those going to the city for some reason or another. There is however a fair population of riders that are station to station commuters, and do not ever normally touch either end of the line (a good example of this is the workers who use the train to get from Bridgeport to the richer towns around it). The conductors on the line tend to be accommodating, and if they see you often enough or are traveling with little children who are psyched to be on a train they will become friendly.
The New Haven Line is a functional system that while having its own issues for the most part works fairly smoothly, and does accomplish its task in giving a mode of transport without a car to New York. (See Finding Parking in New York for horror stories I am sure.)