Commuter rail in the context of "Chicago Union Station"

Inter-city rail services are express trains that run services that connect cities over longer distances than commuter or regional trains. They include rail services that are neither short-distance commuter rail trains within one city area nor slow regional rail trains stopping at all stations and covering local journeys only. An inter-city train is typically an express train with limited stops and comfortable carriages to serve long-distance travel.

Inter-city rail sometimes provides international services. This is most prevalent in Europe because of the proximity of its 50 countries to a 10,180,000-square-kilometre (3,930,000-square-mile) area. Eurostar and EuroCity are examples. In many European countries, the word InterCity or Inter-City is an official brand name for a network of regular-interval and relatively long-distance train services that meet certain criteria of speed and comfort. That use of the term appeared in the United Kingdom in the 1960s and has been widely imitated.

Shinjuku Station (新宿駅, Shinjuku-eki) is a major railway station in Tokyo, Japan, that serves as the main connecting hub for rail traffic between central/eastern Tokyo (the special wards) and Western Tokyo on the inter-city rail, commuter rail, and subway lines. The station straddles the boundary between the Shinjuku and Shibuya special wards. In Shinjuku, it is in the Nishi-Shinjuku and Shinjuku districts; in Shibuya, it is in the Yoyogi and Sendagaya districts.

The station was used by an average of 3.59 million people per day in 2018, making it the world's busiest railway station by far (and registered as such with Guinness World Records). The main East Japan Railway Company (JR East) station and the directly adjacent private railways have a total of 35 platforms, an underground arcade, above-ground arcade and numerous hallways with another 17 platforms (52 total) that can be accessed through hallways to five directly connected stations without surfacing outside. The entire above/underground complex has well over 200 exits.

Nassau County (/ˈnæsɔː/ NASS-aw) is a suburban county located on Long Island, immediately to the east of New York City, bordering the Long Island Sound on the north and the open Atlantic Ocean to the south. As of the 2020 United States census, Nassau County's population was 1,395,774, making it the sixth-most populous county in the State of New York, and reflecting an increase of 56,242 (+4.2%) from the 1,339,532 residents enumerated at the 2010 census. Its county seat is Mineola, while the county's largest and most populous town is Hempstead.

Situated on western Long Island, the County of Nassau borders New York City's borough of Queens to its west, and Long Island's Suffolk County to its east. It is the most densely populated and second-most populous county in the State of New York outside of New York City, with which it maintains extensive rail and highway connectivity, and is considered one of the central counties within the New York metropolitan area.

30th Street Station, officially William H. Gray III 30th Street Station, is a major intermodal transit station in Philadelphia, Pennsylvania, United States. The station opened in 1933 as Pennsylvania Station–30th Street, replacing the 1881 Broad Street station as the Pennsylvania Railroad's main station in the city. The station is the third-busiest Amtrak station in the nation with over 4.1 million passengers as of 2023.

30th Street Station is currently metropolitan Philadelphia's main railroad station and a major stop on Amtrak's Northeast and Keystone corridors. The station is also a major commuter rail station served by all SEPTA Regional Rail lines and is the western terminus for NJ Transit's Atlantic City Line. The station is also served by several SEPTA-managed city and suburban buses and by NJ Transit, Amtrak Thruway, and various intercity operators.

Regional rail is a public rail transport service that operates between towns and cities. These trains operate with more stops than inter-city rail, and unlike commuter rail, operate beyond the limits of urban areas, connecting smaller cities and towns.

In North America, "regional rail" is often used as a synonym for "commuter rail", while in other places "commuter rail" refers to systems that primarily or only offer service during rush hour while "regional rail" refers to systems that offer all-day service. In Europe, regional trains have their own category, often abbreviated to R (RB in Germany) or L (for local train).

In public transit, particularly bus, tram, or train transportation, a limited-stop (or sometimes referred to as semi-fast) service is a trip pattern that stops less frequently than a local service. Many limited-stop or semi-fast services are a combination of commuter rail and express train.

The term is normally used on routes with a mixture of fast and slow services, and can differ in meaning, depending on how it is used by different transit agencies. The main benefits of limited-stop or semi-fast services is the ability to utilise skip-stop calling pattern to maximise capacity along the line, as opposed to a commuter service stopping at every station which slows trailing express trains down.

An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or on-board energy storage such as a battery or a supercapacitor. Locomotives with on-board fuelled prime movers, such as diesel engines or gas turbines, are classed as diesel–electric or gas turbine–electric and not as electric locomotives, because the electric generator/motor combination serves only as a power transmission system.

Electric locomotives benefit from the high efficiency of electric motors, often above 90% (not including the inefficiency of generating the electricity). Additional efficiency can be gained from regenerative braking, which allows kinetic energy to be recovered during braking to put power back on the line. Newer electric locomotives use AC motor-inverter drive systems that provide for regenerative braking. Electric locomotives are quiet compared to diesel locomotives since there is no engine and exhaust noise and less mechanical noise. The lack of reciprocating parts means electric locomotives are easier on the track, reducing track maintenance. Power plant capacity is far greater than any individual locomotive uses, so electric locomotives can have a higher power output than diesel locomotives and they can produce even higher short-term surge power for fast acceleration. Electric locomotives are ideal for commuter rail service with frequent stops. Electric locomotives are used on freight routes with consistently high traffic volumes, or in areas with advanced rail networks. Power plants, even if they burn fossil fuels, are far cleaner than mobile sources such as locomotive engines. The power can also come from low-carbon or renewable sources, including geothermal power, hydroelectric power, biomass, solar power, nuclear power and wind turbines. Electric locomotives usually cost 20% less than diesel locomotives, their maintenance costs are 25–35% lower, and cost up to 50% less to run.

Headway is the distance or duration between vehicles in a transportation system. The minimum headway is the shortest such distance or time achievable by a system without a reduction in the speed of vehicles. The precise definition varies depending on the application, but it is most commonly measured as the distance from the tip (front end) of one vehicle to the tip of the next one behind it. It can be expressed as the distance between vehicles, or as time it will take for the trailing vehicle to cover that distance. A "shorter" headway signifies closer spacing between the vehicles. Airplanes operate with headways measured in hours or days, freight trains and commuter rail systems might have headways measured in parts of an hour, metro and light rail systems operate with headways on the order of 90 seconds to 20 minutes, and vehicles on a freeway can have as little as 2 seconds headway between them.

Headway is a key input in calculating the overall route capacity of any transit system. A system that requires large headways has more empty space than passenger capacity, which lowers the total number of passengers or cargo quantity being transported for a given length of line (railroad or highway, for instance). In this case, the capacity has to be improved through the use of larger vehicles. On the other end of the scale, a system with short headways, like cars on a freeway, can offer relatively large capacities even though the vehicles carry few passengers.