Russia´s First High Speed Train Sapsan, Moscow To St. Petersburg

In most countries, such as the United Kingdom, the distinction between a tramway and a railway is precise and defined in law. In the US and Canada such street railways are mostly referred to as trolleys. The key difference between a railroad and a trolley system is the latter running primarily on public streets, whereas trains have a right of way separated from the public. Often the US style interurban and modern light rail are confused with a trolley system, as it too may run on on the street for short or medium long sections. In some languages the word tram also refers to interurban and light rail -style networks, in particular Dutch.
The length of a tram or trolley may be determined by national regulations. Germany has the so-called Bo-Strab standard, restricting the length of a tram to 75 meters, while in the US, vehicle length is normally restricted by local authorities, often allowing only a single type of vehicle to operate on the network.
• Light rail
The term light rail is sometimes used for a modern tram system, but it may also mean an intermediate form between a tram and a train, similar to a subway except that it may have level crossings. These are then usually protected with crossing gates. In US terminology these systems are often referred to as interurban, as they connect larger urban areas in the vicinity of a major city to that city. Modern light rail systems often use abandoned heavy rail rights of way (e.g. former railway lines) to revitalize deprived areas and redevelopment sites in and around large agglomerations.