Port Authority Trans Hudson (PATH) is New York City's other subway network and connects via two sets of tubes beneath the Hudson River both downtown and midtown Manhattan with Jersey City and Hoboken, New Jersey with one line stretching all the way to Newark. It's a small, just 13.8 miles, system with only 13 stations (2 underground stations abandoned, 1-19th Street still visible from passing trians). PATH is a real network, not a single transit line: 4 different train routes operate during weekdays, and (like the New York City Subway, PATH is a 24 hour operation) 2 routes operate during the overnight hours and on weekends with trains stopping at the Hoboken Station by entering, switching ends (reversing direction) and then leaving again.

PATH's original name was the Hudson and Manhattan Railroad, called the H&M Tubes, or McAdoo Tubes (in honor of Williams Gibbs McAdoo who built the system) and was originally designed to connect the three terminuses of mainline railroads — Lackawana at Hoboken, Erie at the now called Newport Station, and Pennsylvania Railroad at Exchange Place — with Manhanhattan. The Uptown tubes opened to 19th Street on February 26, 1908 and the downtown Manhattan Tubes opened on July 19, 1909. The system was the first fixed link to be built across the Hudson River between New Jersey and Manhattan and provide the first alternative to the mainly railroad operated ferry boats that were previously the only way to cross the Hudson River. The Pennsylvania Railroad opened its twin North River Tunnels in 1910. Today, these are still the only six railroad tracks beneath the Hudson River between Manhattan and New Jersey. The system was extended to its current network, still operating today reaching Newark at the Park Place terminus on November 26, 1911. PATH schedules are still found in New Jersey Transit Rail Timetables for all lines (although through fares aren't offered) from Hoboken or Newark to World Trade Center to show the transfer options to Lower Manhattan.

Since 1911, there have been no extensions the H&M Tubes just rebuilding and rerouting. In 1937, as part of a project with the Pennsylvania Railroad, the Newark and Harrison Stations were rebuilt and trains were rerouted slightly south of their original alignment into the new Newark-Penn Station. Newark Penn Station replaced the original Manhattan Transfer station (located in the New Jersey Meadowlands, with no street access, just a transfer point) for passengers connecting from Pennsylvania Railroad trains to the H&M system. The line between Journal Square and Newark (and only portion of PATH not underground) was shared with Pennsylvania Railroad trains, the remains of a catenary system is still visible. The line doesn't share any trackage with mainline railroads anymore, although it still shares ROW around Harrison and there is one switch. It still operates under a number of grandfather waivers from the FRA because of this legacy. There are more grab holds on PATH cars and train operators are federally certified locomotive engineers. PATH engineers and conductors are also under the federal railway hours of service regulations.

A combination of factors, from the opening of road crossings; the Holland Tunnel in 1927, George Washington Bridge in 1931 and Lincoln Tunnel between 1937 and 1957 (the three tubes opened over a 20 year timespan) to the decline of railroad travel led to the H&M Tubes bankruptcy in the 1950s, although operations continued. The railroads the H&M originally provided connections for began to also offer Motorcoach connections via the new road tunnels into Manhattan. As part of the agreement to build the World Trade Center the Port Authority took over the Hudson & Manhattan Tubes, giving the system the new name of Port Authority Trans Hudson (PATH) in 1962 and started rebuilding the decrepit system. The last ferry boat operating across the Hudson River ceased operations in 1967 from Hoboken. In 1989, the privately operated NY Waterway restored ferry service to the Hudson River. As part of the World Trade Center project, a new downtown terminal opened in 1971 — it is in the process of being rebuilt again after the 9/11 attacks (see its station page for a complete history). Real estate development along the former railroad yards in Jersey City and Hoboken revitalized and gave new life to the PATH system. Today PATH is a vibrant, crowded system; connecting New York City to Jersey City, Hoboken and Newark, like the subway running 24 hours a day. It is an old system, particularly subject to flooding from its waterfront service with service impacted for months after Superstorm Sandy in October 2012.

Rolling Stock: From 2008 to 2011 the entire PATH fleet of cars built between 1965 and 1987 (the PA1, PA2, PA3, and PA4) were replaced by new and modern PA5 cars. These modern cars, with automated announcements and TV monitors display ads and other programming are the only cars in service. The PA5 cars are also the first cars on PATH without a railfan seat, this means there are no longer front views for regular passengers of the rails.

Fare Payment:
PATH is completely separately from the MTA New York City Subway with separate fares (one fare for any distance) and no free transfers or interagency passes between the MTA or New Jersey Transit Rail, Bus, and Light Rail (PATH connects with both the Hudson Bergen Light Rail and Newark City Subway). Today's base fare is similar to the NYC subway at $2.25 (going up 25 cents per year through 2014 to $2.75), fares were lower than subway fares for many years, costing just $1 from 1987 to . Starting in 2003, it did begin a fare modernization project installing new turnstiles (the first station was the reopened World Trade Center PATH Station) and now accepts pay-per-ride MetroCards that deduct the current PATH fare (with fare hikes at different times from the MTA it fluctuates but is usually similar to the going subway fare). PATH turnstiles require inserting a MetroCard in a fare gate (like a QuickCard as a brochure said when PATH began accepting MetroCards). This MetroCard is put through a slot at the front of the fare gate and pops up above it. QuickCards were PATH's original magnetic strip stored value cards. They were slightly older than the MetroCard, implemented (replacing change and tokens) in 1990, and were single use paper cards.

In addition to these farecard options every station had at least one or two turnstiles attached to a cash accepting machine (including after turnstile modernization). These machines were fairly large and tall silver boxes (all have been removed) directly connected to a turnstile and accepted both dollar bills and coins. A passenger entered enough money to cover one fare (they even gave small amounts of change back) and the turnstile was unlocked for one entry. They were all removed or disabled by March 2, 2008. Phasing out one of the more unique fare payment options of any transit system in the United States. One impediment to their retirement was that Reduced Fare users had to insert a special PATH reduced fare card into this machine and pay the half fare. MTA issued half-fare MetroCards are not and have never been accepted on PATH. Reduced Fare users now use a Senior PATH SmartLink Card for payment of half-fares.

Frequent riders can also use a SmartLink Card (costing $5 to purchase) introduced beginning in 2007. Until the Introduction of OMNY in 2019, SmartLink t is the only modern RFID chip based Smartcard currently in operation in the NYC region and is only accepted on PATH. This allows passengers to buy rides in bulk (10, 20, or 40 rides), with a much greater 25% discount than the measly 5% bonuses on pay-per-ride MetroCards. From 2010 through 2016, these fare products could also be purchased on a non-reusable paper based SmartLink Grey card from select newsstands (without a $5 card fee). A SmartLink card is also the only way to buy an Unlimited Ride pass for 1 day (the full price of 3 rides), 7 days, or 30 days.