Rail transport operations

A railway has two major components: the infrastructure (the permanent way, tracks, stations, freight facilities, viaducts, tunnels, etc.)

In some places (notably, most of North America) private railway companies own and operate both the infrastructure and rolling stock (for example, Union Pacific).

The operation of the railway is through a system of control, originally by mechanical means, but nowadays more usually electronic and computerized.

On timetable, train order, and token-based systems, blocks usually start and end at selected stations.

With moving block, lineside signals are not provided, and instructions are passed directly to the trains.

There are generally speaking two ways of validating a ticket: Some passenger cars, especially in long-distance high-speed trains, have a restaurant or bar.

A unit train (also called a block train), which carries a block of cars all of the same origin and destination, does not get sorted in a classification yard, but may stop in a freight yard for inspection, engine servicing and/or crew changes.

In engine facilities, or a traction maintenance depot, locomotives are cleaned, inspected for wear, repaired, updated, or otherwise improved.

Decommissioned locomotives with steam generation capacities were sometimes positioned in semi-permanent locations and their boiler capacity was used to provide steam to heat facilities, power machinery, warm passenger cars, or snow and ice clearing activities such as defrosting railroad switches in cold weather conditions.

If the equipment is considered completely un-serviceable, and it is financially unwise to attempt to make it so, the entire machine may be declared scrap and is usually sold to be taken away and dismantled for recycling of the raw materials.

Steam locomotives were frequently housed in a circular train depot, known as a roundhouse that surrounded a turntable.

The presence of a work train on a given section of track will temporarily decrease the capacity of the route.

It is therefore more economically viable to plan such track occupations for periods of reduced usage (e.g. 'off-peak', overnight or holiday times) to minimise the impact on normal services and revenue.

Each transport system represents a contribution to a country's infrastructure, and as such must make economic sense or eventually close.

Rail transport systems are built into the landscape, including both the physical geography (hills, valleys, etc.)

Rail transport systems are often used for purposes they were not designed for, but have evolved into due to changes in human geography.

In many countries, rail subsidies allow unprofitable, but socially desirable, railways to continue to operate.