Level crossing
The term level crossing (American English: grade crossing) -- i.e. a crossing on one level, or "at grade", without recourse to a bridge or tunnel -- is used with particular reference to the situation where a road crosses a railway line in such circumstances.
It also applies when a light rail line with separate right-of-way crosses a road; the term "metro" usually means by definition that there are no level crossings.
There are standard signs and markings for drivers to warn of such a crossing, varying of course by nation and region. Many of these crossings are blocked with gates of various kinds when a rail vehicle will be using the track. Often there are lights and audible warnings.
In the United States, and in countries that take their railroad practice from US practice, a train must have a bell that sounds continually until the train is completely past the crossing, and the whistle or horn must be sounded as the train approaches the crossing. Some American cities, citing noise pollution abatement, pass laws prohibiting the sounding of bells and whistles, but their ability to enforce such rules is debatable. In December of 2003, The US Federal Railroad Administration published regulations that would create areas where train horns could be silenced, given that certain safety measures were put in place. More information can be found at the FRA website at and following the page link under 'Train horn rule.' The regulations are scheduled to go into effect in December of 2004.
Third rail electric systems may also have level crossings: there is a gap in the third rail over the level crossing, but in spite of that the power supply is not interrupted since trains have current collectors at each of their ends.
On many level crossings where a busy road crosses a railway, automatic gates or barriers are lowered when a train approaches, to prevent a collision. On less important roads and railway lines level crossings are often "open" without gates to protect them, but these often have some kind of warning lights to warn of approaching trains. Unguarded crossings represent a serious safety issue. Railways in the US are adding reflectors to the side of each train car to help prevent accidents at level crossings.
Modern railways avoid level crossings with flyovers or overpasses/underpasses.
At railway stations a pedestrian level crossing is sometimes provided to allow passengers to reach other platforms in the absence of an underpass or bridge.
External links
- Cost-effective Systems for Railway Level-Crossing Protection from the UN Economic and Social Commission for Asia and the Pacific
- Train horn rule at the US Federal Railroad Administration