View source for Four-quadrant gate

{{Short description|Level crossing protective system with four barriers}}
{{More citations needed|date=February 2019}}[[Image:Level crossing - Chertsey - England - 270404.jpg|thumbnail|right|250px|A level crossing with manually-controlled full barriers at Chertsey, England. The barriers are rising.]]

A '''four-quadrant gate''' or full-barrier equipment is a type of [[boom barrier]] gate protecting a [[grade crossing]]. It has a gate mechanism on both sides of the tracks for both directions of automotive traffic. The exit gates blocking the road leading away from the [[rail track|tracks]] are equipped with a delay, and begin their descent to their horizontal position several seconds after the entrance gates do, so as to avoid trapping highway vehicles on the crossing. In the United Kingdom, the exit-side barriers do not lower until the entrance-side barriers have lowered.

Many people consider four-quadrant gates to be safer than two-quadrant gates because they prevent drivers from illegally and dangerously driving their vehicles around lowered gates, in an attempt to pass before the [[train]] does. However, these gates are only safer if there is a way of ensuring that the crossing is clear before clearing the train driver's signals and allowing them to pass, as is always the case in the United Kingdom. As a result, the barriers are lowered for long periods before the train arrives, providing enough time that the train can be stopped if the crossing is obstructed.

In the United Kingdom, such crossings are categorised as [[Level crossings in the United Kingdom|manually-controlled barriers]] (MCB) because they are almost always controlled from a signal box or centre. Some are known as MCB-CCTV level crossings, where they are supervised by video link to the signal box from which they are remotely controlled. The gates can also be operated automatically, as long as the crossing is still checked for obstruction with a suitable detection technology.

The first four-quadrant gate in the United States was installed in 1952.<ref name="schoolstreet">{{cite web|url=https://railroads.dot.gov/sites/fra.dot.gov/files/fra_net/407/ord0709.pdf|title=Evaluation of the School Street Four-Quadrant Gate/In-Cab Signaling Grade Crossing System|last1=Hellman|first1=Adrian D.|last2=Carroll|first2=Anya A.|date=March 2007|website=|publisher=Federal Railroad Administration|access-date=1 February 2020|last3=Chappell|first3=Debra M.}}</ref>{{Rp|7}} They have become common for new installations and replacements since. Unlike the UK, many are automated by the rail line's signal system. The first quad gate installation in the country with sensors to detect vehicles stopped in the tracks was installed in [[Groton, Connecticut]] in 1998.<ref>{{cite news |url=https://news.google.com/newspapers?id=RgohAAAAIBAJ&sjid=ynYFAAAAIBAJ&pg=1307%2C568388 |title=Stuck crossing gate strands drivers on wrong side of the tracks |newspaper=The Day |date=4 November 1999 |access-date=22 March 2015}}</ref> Eight of the eleven remaining [[Northeast Corridor#Grade crossings|grade crossings on the Northeast Corridor]] now have such setups.<ref>{{cite news |url=https://www.courant.com/1999/09/09/amtrak-to-put-up-7-safer-gates/ |title=Amtrak To Put Up 7 Safer Gates |newspaper=[[Hartford Courant]] |last=Dee |first=Jane E. |date=9 September 1999 |access-date=22 March 2015 |archive-date=2 April 2015 |archive-url=https://web.archive.org/web/20150402122329/http://articles.courant.com/1999-09-09/news/9909090176_1_grade-crossings-acela-express-trains-high-speed-rail-corridors |url-status=live }}</ref>

In American English, "gates" are used to describe level crossing barriers, as there are no longer traditional, opening gates. In British English, "barriers" refers to level crossing barriers, as some crossings still have actual gates.

==References==
{{Reflist}}

[[Category:Level crossings]]
[[Category:Protective barriers]]
[[Category:Road infrastructure]]
[[Category:Street furniture]]

== Further reading ==
* {{Cite web
| title = Grade Crossing Safety 2016 | website = [[BNSF Railway]]
| access-date = 27 February 2019 | quote = archived
| url = https://www.bnsf.com/in-the-community/pdf/grade-crossing-safety.pdf | archive-url = https://web.archive.org/web/20190228004157/https://www.bnsf.com/in-the-community/pdf/grade-crossing-safety.pdf | url-status = dead | archive-date = 2019-02-28 }}
* {{Cite web
| title = Glossary of Terms Applied to Highway-Railroad Grade Crossing Warning Gates and Signals
| work = fdotwww.blob.core.windows.net
| access-date = 27 February 2019
| url = https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/content/rail/publications/studies/safety/4quad/glossaryofterms.pdf?sfvrsn=311177fb_0
}}
* {{Cite web
| title = Quad Gates
| author = Island Radar
| work = islandradar.com
| access-date = 27 September 2023
| url = https://www.islandradar.com/products/quad-gate
}}

{{rail-transport-stub}}
{{road-stub}}