Multiple unit
[3] The multiple-unit traction control system was developed by Frank Sprague and first applied and tested on the South Side Elevated Railroad (now part of the Chicago 'L') in 1897.
India's ICF announced the country's first high-speed engine-less train named 'train 18', which would run at 250 km/h maximum speed.
Most of them have cabs at both ends, resulting in quicker turnaround times, reduced crewing costs, and enhanced safety.
The faster turnaround time and the reduced size (due to higher frequencies) as compared to large locomotive-hauled trains, has made the MU a major part of suburban commuter rail services in many countries.
Another side effect of this is reduced track wear, as traction forces can be provided through many axles, rather than just the four or six of a locomotive.
Separate locomotives mean that the costly motive power assets can be moved around as needed and also used for hauling freight trains.
A multiple unit arrangement would limit these costly motive power resources to use in passenger transportation.
It is difficult to have gangway connections between coupled units and still retain an aerodynamic leading front end.
Likewise, in such instances, buffet cars and other shared passenger facilities may need to be duplicated in each unit, reducing efficiency.
The passenger environment of a multiple unit is often noticeably noisier than that of a locomotive-hauled train, due to the presence of underfloor machinery.
Gautrain, a commuter rail system in Johannesburg, operates with Bombardier Electrostar electric multiple units.
The concept of multiple unit has entered the horizon of the Chinese since the 6th Speed-up Campaign of China Railway in 2007.
This was the beginning of the general service of multiple unit trains in China's national railway system.
Far earlier than the introduction of CRH brand, multiple unit trains have been running on all major cities' metro lines in China.
In Japan almost all passenger trains, including the high-speed Shinkansen, are of the multiple-unit (MU) type, with most locomotives now used solely in freight operations.
Japan is a country of high population density with a large number of railway passengers in relatively small urban areas, and frequent operation of short-distance trains has been required.
Therefore, the high acceleration ability and quick turnaround times of MUs have advantages, encouraging their development in this country.
This work resulted in the original Shinkansen development which optimized all of the EMU's efficiencies to maximize speed.
Swedish railroads have been privatized in steps for about 25 years, and today many different companies operate different types of multiple units.
In the UK the use of modern diesel multiple units was pioneered in Northern Ireland,[citation needed] although a number of other railway companies also experimented with early DMUs (including the Great Western and the London Midland Scottish).
They were originally introduced as steam locomotive hauled carriages but were converted to electric traction from 1919 during Melbourne’s electrification project.
[9] Indian Railways has recently introduced a semi-high-speed EMU named Vande Bharat Express, capable of running at 183 km/h (114 mph).
The locally-built MC class was initially powered by gasoline and was changed to diesel during World War II.
Both the MRR and its successor, the Philippine National Railways (PNR), has since acquired various classes of diesel multiple units.
All multiple units owned by MRR and all of the older MUs of the PNR were built by Japanese firms.
[10] The first electric multiple units were acquired in 1984 for the LRT Line 1 built by La Brugeoise et Nivelles in Belgium.
The Southeastern Pennsylvania Transportation Authority (SEPTA) Regional Rail Division uses EMUs almost exclusively — the exception being some of its peak express service.
DMUs are less common, partly because new light rail operations are almost entirely electric, with many commuter routes already electrified, and also because of the difficulties posed by Federal Railway Administration rules limiting their use on shared passenger/freight corridors.
When the Budd RDC was developed following World War II, it was adopted for many secondary passenger routes in the United States (especially on the Boston and Maine Railroad) and Canada.
[13] These two car units ran along the Bloor Street route only beginning in 1950 and ceased operations after the opening of the Bloor–Danforth subway line in 1966.
