A growing number of urban electric transport systems is helping to improve the quality of life in cities across the world.
Cities around the world, from Edinburgh to Melbourne, have been turning to trams to tackle increasing traffic congestion and escalating air pollution. They present two major advantages: they are zero pollution vehicles at the point of use and they have a large transport capacity of up to 300.
The Edinburgh tramways project was initially unpopular, but after only two years the operators have not only achieved pre-tax profitability, but also exceeded the original ridership targets. Last year, a passenger survey recorded a 99 per cent satisfaction rating.
Tramlines were ripped up in the 1960s in favour of diesel fuelled buses, but the backlash in recent years against pollution and dependence on fossil fuels has seen a resurgence of interest in electric trams. Market growth is mainly driven by new tram and electric light rail urban transport projects under way on most continents.
The difference between trams, or streetcars as they are known in the US, and light railways is not always clear and the terms are sometimes interchangeable. Light rail systems use small electric-powered trains or trams that generally have a lower capacity and lower speed than normal trains to serve large metropolitan areas.
They usually operate at ground level, but can include underground or overhead zones.
All urban rail systems rely on International Standards developed by IEC Technical Committee (TC) 9: Electrical equipment and systems for railways. Areas covered include rolling stock, fixed installations, management systems (including communication, signalling and processing systems) for railway operation, their interfaces and their ecological environment.
These standards deal with electromechanical and electronic aspects of power components as well as electronic hardware and software components.
Other IEC TCs and Subcommittees (SCs) central to the development of urban electric transport are:
> IEC TC 20: electric cables
> IEC TC 69: Electric road vehicles and electric industrial trucks
> IEC TC 21: Secondary cells and batteries, and SC 21A: Secondary cells and batteries containing alkaline or other non-acid electrolytes. Standardization work for batteries used in electric vehicles and electric industrial trucks is the responsibility of Joint Working Groups set up with IEC TC 69
> IEC JWG 69 Li: TC 21/SC 21A/TC 69 – Lithium for automobile/automotive applications
> IEC JWG 69 Pb-Ni: TC 21/SC 21A/TC 69 – Lead acid and nickel based systems for automobile/automotive applications
> IEC TC 22: power electronic systems and equipment
> IEC TC 32: fuses
> IEC TC 40: Capacitors and resistors for electronic equipment; develops International Standards for electric double layer capacitors (better known as supercapacitors)
> IEC SC 48B: Electrical connectors
> IEC TC 105: Fuel cells
Standardization work by these IEC TCs and SCs underpins the widespread adoption of urban electric transport systems. They are helping to improve the health and quality of life of hundreds of millions across the world, as well as cutting the negative environmental impact of mass transportation systems.