Every little bit helps but it's no solution.
The Pelosis will just use it as a smoke screen reason to delay drilling and converting to NG and coal.
Safety
An unguarded electrified rail carrying more than 50 volts is a safety hazard, and some people have been killed by touching the rail or by stepping on it while attempting to cross the tracks. However, such incidents are usually the result of carelessness on the part of the victim. The principal hazard is probably associated with level crossings. While their number on third rail lines is normally reduced to none, they still occur at some systems, particularly on rural and suburban portions of the network. One notable example of a Metro line running a third rail at ground level is the outer ends of the present Brown Line and Pink Line of the Chicago 'L', running on street level in a densely populated neighborhood. The conductor is discontinued in the level crossing area. Pedestrians may be discouraged from trespassing into railway area by means of perforated panels difficult to step on (cattle-cum-trespass guards). They are laid between rails alongside the road.
Intercity ground level third rail systems are the norm in the southeast of England, and level crossings are handled in a fashion similar to the Chicago system. A few interurban electric railways attempted to utilize third rail in the USA, but these were quickly abandoned as impractical outside New York City commuter lines such as the Long Island Rail Road. Both the US and UK intercity systems address safety through extensive fencing and warning signage.
There are urban legends that people have died while urinating on the third rail (the urine stream supposedly completes an electrical circuit that electrocutes the victim); a non-continuous stream has been demonstrated by MythBusters (Season 1, Episode 3) to be unable to conduct electricity [2]. This myth may be partially perpetuated by a 1977 incident that occurred in Chicago where an intoxicated pedestrian suffered a fatal electrocution injury while trespassing to urinate on the grade-level CTA Brown Line near Kedzie Avenue. However, the death occurred as a result of the passenger making physical contact with the third rail, not as a result of an electrical circuit being completed via his urine stream[3]. However a recent event at Vauxhall station in London may perpetuate this myth (see thesun.co.uk.
The third rails used on the BART system. The rail changes location relative to the train upon entering the station for safety reasons (see article for more information).There are also myths about people urinating on overhead wires from a bridge. Also people have been killed by overhead wires while passing a standing train by climbing over it. So both variants of electric supply are dangerous.
[edit] Solutions to safety issues
A new tramway in Bordeaux, France surmounts the safety problem by using a third rail divided into insulated segments only a few metres long. Each segment is live only while completely covered by a tram, so there is no risk of a person or animal coming into contact with a live rail (see Third-rail power for trams and stud contact electrification for more information). This system would not be suitable for higher speeds, and the cost of breaking the live rail into short sections is considerable. This system was developed mainly for aesthetic reasons, to avoid overhead wires in front of the town hall.
Other safety precautions can be made to reduce the risk of the third rail. Many subways, such as BART and the Washington Metro, use sheaths to cover their third rails and always place the rail on the further side of the track away from where passengers would normally be. If someone falls on the tracks, there is room to return safely to the platform (or crawl under the platform) without stepping on the third rail.
[edit] Limited capacity
A relatively low voltage is necessary in a third-rail system — otherwise, electricity would arc from the rail to the ground or the running rails — but the resulting higher current (sometimes upwards of 3,000 amperes) causes more proportional voltage drop per mile, meaning that electrical feeder sub-stations have to be set up at frequent intervals along the line (generally no more than 10 miles (16 km) apart), increasing operating costs. A 1992 report, prepared for the California Department of Transportation by Morrison-Knudsen Corporation, states that typical spacing of substations supplying a 600 volt DC track is one mile apart, and the cost of electrifying with third rail is nearly double that of overhead catenary.[1] The low voltage also means that the system is prone to overload, which makes such systems unsuitable for freight or high-speed trains demanding high amounts of power. These limitations of third-rail systems have largely restricted their use to mass transit systems. Capacity is also limited by speed restrictions. Testing on the southern region of British Rail during the late 1980s/early 1990s established that third rail could handle 160 km/h (100 mph) and that third rail could provide reliable current collection. Testing at greater speeds was not tried as the track tested had a maximum speed of 160 km/h (100 mph).[2]
By comparison, overhead wires can provide 50 kV, and can take roughly ten times the power[citation needed].
[edit] Infrastructure restrictions
Junctions and other pointwork make it necessary to leave gaps in the live rail at times, as do level crossings. This is not usually a problem, as most third-rail rolling stock has multiple current collection shoes along the length of the train, but under certain circumstances it is possible for a train to become "gapped" — stalled with none of its shoes in contact with the live rail. When this happens, it is usually necessary for the train to be shunted back onto a live section either by a rescue locomotive or another service train, although in some circumstances it is possible to use jumper cables to temporarily hook the train's current collectors to the nearest section of live rail. Given that gapping tends to happen at complex, important junctions, it can be a major source of disruption. On the Chicago Transit Authority system the jumper cables are known as stingers; they are insulated poles with a wired contact that may be manually pressed against contact shoes to restart a gapped train. Other such problems are implementation-specific and usually have workarounds. Another infrastructure restriction of third rail is that the rail and its safety cover decrease the structure gauge and in turn the loading gauge, potentially blocking access to certain types of equipment.
When David L. Gunn became General Manager of the Washington DC Metro Rail system in 1991, he proposed to alleviate crowding by running much more frequent trains as two-car trains instead of the practice the transit authority had of running four-car trains. He had to publicly drop this idea, with some embarrassment, when it was pointed out to him that two-car trains can operate only in specific areas of the system because each car only has one shoe, on the same side of the car. Even with the practice of having each car pointing in the opposite direction so that there is a shoe on each side of the train, there are many places in the system where a two-car train would end up gapped.[citation needed]
[edit] Inefficient contact
Fallen leaves, snow and other debris on the conductor rail can reduce the efficiency of the contact between the conductor rail and the pickup shoes, leaving trains stalled because of the lack of power. Bottom-contact third rail, as used on the Metro-North Railroad (see Technical aspects above), and numerous other transit systems including the Docklands Light Railway in London and the Market-Frankford Line in Philadelphia, is highly resistant to this problem.
Older systems adopted top-contact third rail before they realised that there would be problems with leaves, etc., while newer systems have learned from this mistake and use side or bottom contact. However, some relatively new systems in North America, such as the TTC in Toronto, use top-covered top-contact third rails on above-ground portions of its subway system; rarely is the system delayed by electrical problems even after heavy snows. Problems generally arise in other aspects of the system (frozen switches for example) long before snow interferes significantly with electrical pickup. Some systems are less susceptible to this problem due to having mostly underground trackage, or less severe weather. |
