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| Line 1: |
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| {{Original research|date=September 2008}}
| | If you are looking for a specific plugin, then you can just search for the name of the plugin. Good luck on continue learning how to make a wordpress website. This CMS has great flexibility to adapt various extensions and add-ons. When you loved this informative article and you would want to receive more details concerning [http://deurl.de/wordpress_backup_plugin_646780 backup plugin] kindly visit our own internet site. Out of the various designs of photography identified these days, sports photography is preferred most, probably for the enjoyment and enjoyment associated with it. In the most current edition you can customize your retailer layout and display hues and fonts similar to your site or blog. <br><br>Right starting from social media support to search engine optimization, such plugins are easily available within the Word - Press open source platform. The higher your blog ranks on search engines, the more likely people will find your online marketing site. We also help to integrate various plug-ins to expand the functionalities of the web application. Furthermore, with the launch of Windows 7 Phone is the smart phone market nascent App. Once you've installed the program you can quickly begin by adding content and editing it with features such as bullet pointing, text alignment and effects without having to do all the coding yourself. <br><br>Minor and medium sized corporations also have a lot to obtain by shelling out in a very good website. Note: at a first glance WP Mobile Pro themes do not appear to be glamorous or fancy. I've applied numerous Search engine optimization-ready Word - Press themes and I can say from knowledge that I consider the Genesis Search engine marketing panel one particular of the simplest to use. These frequent updates have created menace in the task of optimization. After that the developer adds the unordered list for navigations. <br><br>Google Maps Excellent navigation feature with Google Maps and latitude, for letting people who have access to your account Latitude know exactly where you are. The SEOPressor Word - Press SEO Plugin works by analysing each page and post against your chosen keyword (or keyword phrase) and giving a score, with instructions on how to improve it. Specialty about our themes are that they are easy to load, compatible with latest wordpress version and are also SEO friendly. Can you imagine where you would be now if someone in your family bought an original painting from van Gogh during his lifetime. Wordpress template is loaded with lots of prototype that unite graphic features and content area. <br><br>Instead, you can easily just include it with our bodies integration field in e - Panel. I don't want that for my visitors and I'm quite sure they don't either. You can select color of your choice, graphics of your favorite, skins, photos, pages, etc. Word - Press is an open source content management system which is easy to use and offers many user friendly features. 95, and they also supply studio press discount code for their clients, coming from 10% off to 25% off upon all theme deals. |
| [[File:CTA loop junction.jpg|thumb|300px|{{convert|90|ft|m|2|adj=on}} radii on the [[Elevated railway|elevated]] {{railgauge|56.5}} [[Chicago 'L']]. There is no room for longer radii at this [[street]] [[Intersection (road)|intersection]]]]
| |
| | |
| The '''minimum railway curve radius''', the shortest design radius, has an important bearing on constructions costs and operating costs and, in combination with [[Cant (road/rail)#Rail|superelevation]] (difference in elevation of the two rails) in the case of [[Track (rail transport)|train tracks]], determines the maximum safe speed of a curve. Superelevation is not a factor on [[tramway track]]s. Minimum radius of curve is one parameter in the design of [[Railroad car|railway vehicles]]<ref>[http://worldtraderef.com/WTR_site/Rail_Cars/Guide_to_Rail_Cars.asp Guide to Railcars, showing the minimum radii that each [[Railroad car#Freight cars|freight car]] is able to negotiate]</ref> as well as [[tram]]s.<ref>[http://transit.toronto.on.ca/streetcar/4503.shtml Canadian Light Rail Vehicle able to negotiate a {{convert|36|ft|m|3|abbr=on}} radius curve]</ref>
| |
| | |
| == History ==
| |
| The first proper railway was the [[Liverpool and Manchester Railway]] which opened in 1830. Like the trams that had preceded it over a hundred years, the L&M had gentle curves and gradients. Amongst other reasons for the gentle curves were the lack of strength of the track, which might have overturned if the curves were too sharp causing derailments. There was no signalling at this time, so drivers had to be able to see ahead to avoid collisions with previous trains. The gentler the curves, the longer the visibility. The earliest rails were made in short lengths of [[wrought iron]], which does not bend like later [[steel]] rails that were introduced in the 1850s.
| |
| | |
| == Factors affecting the minimum curve radius ==
| |
| | |
| Minimum curve radii for railroads are governed by the speed operated and by the mechanical ability of the rolling stock to adjust to the curvature. In North America, equipment for unlimited interchange between railroad companies are built to accommodate {{convert|350|ft|m|1|adj=on}} radius (16 degrees 26 minutes) or sharper, but normally {{convert|410|ft|m|1|adj=on}} radius (14 degrees) is used as a minimum, as some freight cars are handled by special agreement between railroads that cannot take the sharper curvature. For handling of long freight trains, a minimum {{convert|717|ft|m|1|adj=on}} radius (8 degrees) is preferred.
| |
| | |
| The sharpest curves tend to be on the narrowest of [[Narrow gauge railway|narrow gauge]] railways, where almost everything is proportionately smaller.<ref name=Jane />
| |
| | |
| === Steam locomotives ===
| |
| As the need for more powerful (steam) locomotives grew, the need for more driving wheels on a longer, fixed wheelbase grew too. But long wheel bases are unfriendly to sharp curves. Various type of [[articulated locomotive]]s [[Mallet locomotive|Mallet]], [[Garratt locomotive|Garratt]], [[Shay locomotive|Shay]] were devised to avoid having to operate multiple locomotives with multiple crews.
| |
| | |
| More recent diesel and electric locomotives do not have a wheelbase problem and can easily be operated in multiple with a single crew.
| |
| | |
| *The '''[[TGR K Class]]''' was
| |
| **{{railgauge|610}} gauge
| |
| **{{convert|99|ft|m|0|abbr=on}} radius curves
| |
| *'''Example Garratt'''
| |
| **{{RailGauge|1000mm}} gauge
| |
| **{{convert|25|kg/m|lb/yd|2|abbr=on}} rails
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| **Main line radius - {{convert|175|m|ft|0|abbr-on}}
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| **Siding radius - {{convert|84|m|ft|0|abbr-on}} <ref>http://www.garrattmaker.com/history.html</ref>
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| *'''0-4-0'''
| |
| **[[GER Class 209]]
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| **{{railgauge|1435}}
| |
| | |
| === Couplings ===
| |
| Not all [[Coupling (railway)|couplers]] can handle very sharp curves. This is particularly true of the European [[Coupling (railway)#Buffers and chain|buffer and chain couplers]], where the buffers get in the way.
| |
| | |
| === Train lengths ===
| |
| A long heavy freight train, especially those with light and heavy waggons mixed up, may have problems going round very sharp curves, as the [[Railway coupling#Drawgear|drawgear]] forces may pull intermediate waggons off the rails causing derailments. Solutions might include:
| |
| * marshal light and empty waggons at rear of train
| |
| * intermediate locomotives, including remotely controlled ones.
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| * ease curves or deviate line.
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| * reduced speeds
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| * less cant (superelevation), but this is unfriendly to fast passenger trains.
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| * More but shorter trains.
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| * problem is less severe with bulk say coal trains, where all waggons weigh the same.
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| * better driver training
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| * driving controls that display drawgear forces.
| |
| * New c2013 [[Electronically Controlled Pneumatic]] brakes have the potential to reduce errant drawgear forces, besides displaying even more information to the driver.
| |
| | |
| A similar problems occur with harsh changes in gradients (vertical curves).
| |
| | |
| === Speed ===
| |
| As a heavy train goes round a bend at speed, the [[centrifugal force]] the train exerts on the rails is sufficient to move the actual track, which is only held in place by ballast. To counter this, a [[cant (road/rail)|cant]] is used, that is, a height difference between the outside and inside rails on the curve. Ideally the train should be tilted such that resultant (combined) force acts straight "down" through the bottom of the train, so the rails feel little or no sideways force. Some trains are capable of [[tilting train|tilting]] to enhance this effect for passenger comfort.
| |
| | |
| The cant can't of course be ideal at the same time for both fast passenger trains and slow freight trains.
| |
| | |
| The relationship between speed and tilt can be calculated mathematically. Specifically, the [[gravitation]]al and [[centripetal force]]s need to be in the ratio 1 : tan ''θ'', where ''θ'' is the angle by which the train is tilted due to the cant:
| |
| :<math>g=\frac{v^2}{r}\tan\theta</math>
| |
| Geometrically, tan θ can be expressed (approximately, for small angles) in terms of the [[track gauge]] and the [[cant (road/rail)|cant]]:
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| :<math>\tan\theta\approx\sin\theta=\frac{h_a+h_b}{G}</math>
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| Combining these gives
| |
| :<math>g=\frac{v^2}{r}\frac{(h_a+h_b)}{G}</math>
| |
| which rearranges to give the formula for maximum speed on a curve:
| |
| :<math>r=\frac{Gv^2}{g(h_a+h_b)}</math>
| |
| where ''G'' is the [[rail gauge]], ''v'' is speed in m/s (1 m/s = 3.6 km/h), ''g'' is [[gravitational acceleration]] (9.8 m/s²), ''h<sub>a</sub>'' is [[Cant (road/rail)|cant]], and ''h<sub>b</sub>'' is [[cant deficiency]]. The cant deficiency is the amount of additional cant that would be needed to neutralise the centrifugal force, and it is proportional to the curve force.
| |
| | |
| This table shows examples of curve radii. The values used when building high-speed railways vary, and depends on how much wear and safety desired.
| |
| {| class="wikitable"
| |
| |- Class="hintergrundfarbe5"
| |
| ! '''Curve radius'''
| |
| ! ≤ 33 m/s<br/>= 120 km/h
| |
| ! ≤ 56 m/s<br/>= 200 km/h
| |
| ! ≤ 69 m/s<br/>= 250 km/h
| |
| ! ≤ 83 m/s<br/>= 300 km/h
| |
| ! ≤ 97 m/s<br/>= 350 km/h
| |
| ! ≤ 111 m/s<br/>= 400 km/h
| |
| |-
| |
| | [[Cant (road/rail)#Rail|Cant]] 160 mm,<br />cant deficiency 100 mm,<br />no [[tilting train]]s
| |
| | 630 m
| |
| | 1800 m
| |
| | 2800 m
| |
| | 4000 m
| |
| | 5400 m
| |
| | 7000 m
| |
| |-
| |
| | Cant 160 mm,<br />cant deficiency 200 mm,<br />with [[tilting train]]s
| |
| | 450 m
| |
| | 1300 m
| |
| | 2000 m
| |
| | colspan=3 | no tilting trains planned for these speeds
| |
| |}
| |
| | |
| == Transition curves ==
| |
| | |
| {{Main|Track transition curve}}
| |
| | |
| A curve should not become a straight all at once, but should gradually increase in radius over time (a distance of around 40 m - 80 m for a line with a maximum speed of about 100 km/h). Even worse than curves with no transition are [[reverse curve]]s with no intervening straight.
| |
| | |
| The super-elevation (aka [[Cant (road/rail)|cant]]) must also be transitioned. | |
| | |
| The higher the speed, the longer the transition.
| |
| | |
| == Vertical Curves ==
| |
| | |
| As a train negotiates a curve, the force it exerts on the track changes. Too tight a 'crest' curve could result in the train leaving the track as it drops away beneath it; too tight a 'trough' and the train will plough downwards into the rails and damage them. More precisely, the [[normal force|support force]] ''R'' exerted by the track on a train as a function of the curve radius ''r'' is given by
| |
| :<math>R=mg\plusmn\frac{mv^2}{r}</math>
| |
| positive for troughs, negative for crests, where ''m'' is the mass of the train and ''v'' is the speed in m/s. For passenger comfort the ratio of the [[gravitational acceleration]] ''g'' to the [[centripetal acceleration]] ''v<sup>2</sup>/r'' needs to be kept as small as possible, else passengers will feel large 'changes' in their weight.
| |
| | |
| As trains cannot climb steep slopes, they have little occasion to go over significant vertical curves, however [[High Speed 1]] (section 2) in the UK has a minimum vertical curve radius of 10000m.<ref>http://www.whatdotheyknow.com/request/24986/response/79568/attach/3/HS1%20Section%202%20Register%20of%20Infrastructure.pdf - page 19</ref> [[High Speed 2]], with the higher speed of 400 km/h, stipulates much larger 56000m radii.<ref>http://highspeedrail.dft.gov.uk/sites/highspeedrail.dft.gov.uk/files/hs2-route-engineering.pdf - page 4</ref> In both these cases the experienced change in 'weight' is less than 7%.
| |
| | |
| == Problem curves ==
| |
| | |
| * The [[Australian Standard Garratt]] had flangeless leading driving wheels which tended to cause derailments on sharp curves.
| |
| * Sharp curves on the [[Port Augusta, South Australia|Port Augusta]] to [[Hawker, South Australia|Hawker]] line of the [[South Australian Railways]] caused derailment problems when bigger and heavier [[SAR X class]] locomotives were introduced, requiring deviations to ease the curves.<ref>[[Australian Railway History]] September 2008, p291.</ref>
| |
| * {{convert|5|chain|m ft|0|sing=on}} curves on the [[Oberon railway line]], [[Batlow railway line]], and [[Dorrigo railway line]], New South Wales, limited steam locomotives to the [[New South Wales 19 class locomotive|19 class]].
| |
| | |
| == List of minimum curve radii ==
| |
| | |
| {| class="wikitable sortable" border="1"
| |
| |-
| |
| ! scope="col" | Gauge
| |
| ! scope="col" | Radius
| |
| ! scope="col" class="unsortable" | Location
| |
| ! scope="col" class="unsortable" | Notes
| |
| |-
| |
| | |
| | {{railgauge|1435}} || {{convert|7000|m|ft|0|abbr=on}} || [[China]] || Typical China's high-speed railway network (350 km/h)
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|5500|m|ft|0|abbr=on}} || [[China]] || Typical China's high-speed railway network (250 km/h~300 km/h)
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|4000|m|ft|0|abbr=on}} || [[China]] || Typical high-speed railways (300 km/h)
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|3500|m|ft|0|abbr=on}} || [[China]] || Typical China's high-speed railway network (200~250 km/h)
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|2000|m|ft|0|abbr=on}} || [[China]] || Typical high-speed railways (200 km/h)
| |
| |-
| |
| | {{railgauge|1067}} || {{convert|250|m|ft|0|abbr=on}} || [[Democratic Republic of the Congo|DRCongo]] [[Matadi-Kinshasa Railway]] || Deviated {{railgauge|1067}} line.
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|240|m|ft|0|abbr=on}} || [[Cougal Spiral (railway)|Border Loop]] || {{convert|5000|LT|t ST|abbr=on|lk=on}} - {{convert|1500|m|ft|0|abbr=on}}
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|200|m|ft|0|abbr=on}} || [[Wollstonecraft railway station|Wollstonecraft Railway Station, Sydney]] ||
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|200|m|ft|0|abbr=on}} || [[Homebush railway station|Homebush]] triangle || {{convert|5000|LT|t ST|abbr=on|lk=on}} - {{convert|1500|m|ft|0|abbr=on}}
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|190|m|ft|0|abbr=on}} || [[Turkey]] || [[Transport in Turkey|Turkey]]<ref name =Jane>[[Jane's World Railways]] 1995-1996 p728</ref>
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|160|m|ft|0|abbr=on}} || [[NSW]], [[Lithgow Zig Zag|Zig Zag]] || 40 km/h
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|100|m|ft|0|abbr=on}} || [[NSW]], [[Batlow, New South Wales]] || Weight limit: {{convert|500|LT|t ST|abbr=on|lk=on}} <!-- Which ton??? --> and {{convert|300|m|ft|0|abbr=on}} - restricted to [[New South Wales Z19 class locomotive|NSW Z19 class]] [[0-6-0]] steam locomotives
| |
| |-
| |
| | {{railgauge|1067}} || {{convert|95|m|ft|2|abbr=on}} || [[Newmarket, New Zealand]] || Extra heavy concrete sleepers <ref>[[Railway Gazette International]] March, 2012, page 23</ref>
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|85|m|ft|0|abbr=on}} || [[Windberg Railway]] ([[:de:Windbergbahn]]) || (between [[Freital]]-Birkigt and [[Dresden]]-Gittersee) - restrictions to wheelbase
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|61|m|ft|0|abbr=on}} || [[London Underground]] [[Central line]] || (between White City and Shepherd's Bush)
| |
| |-
| |
| | {{railgauge|1067}} || {{convert|60|m|ft|0|abbr=on}} || [[Queensland Railways]] ||
| |
| |-
| |
| | {{railgauge|762}} || {{convert|50|m|ft|0|abbr=on}} || [[Matadi-Kinshasa Railway]] || original {{railgauge|762}} line.
| |
| |-
| |
| | {{railgauge|600}} || {{convert|50|m|ft|0|abbr=on}} || [[Welsh Highland Railway]] ||
| |
| |-
| |
| | {{railgauge|1000}} || {{convert|45|m|ft|0|abbr=on}} || [[Bernina Railway]] ||
| |
| |-
| |
| | {{railgauge|600}} || {{convert|40|m|ft|0|abbr=on}} || [[Welsh Highland Railway]] || on original line at [[Beddgelert]]
| |
| |-
| |
| | {{railgauge|762}} || {{convert|40|m|ft|0|abbr=on}} || [[Narrow gauge lines of the Victorian Railways|Victorian Narrow Gauge]] || {{convert|16|km/h|mph|0|abbr=on|disp=or}} on curves;<br> ({{convert|32|km/h|mph|0|abbr=on|disp=or}} on straight)
| |
| |-
| |
| | {{railgauge|762}} || {{convert|37.47|m|ft|abbr=on}} || [[Kalka-Shimla Railway]] || or 48 degrees
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|29.00|m|ft|abbr=on}} || New York Subway || <ref>[[Railway Gazette International]], July 2012, p18</ref>
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|27.43|m|ft|0|abbr=on}} || [[Chicago 'L']] ||
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|25|m|ft|0|abbr=on}} || [[Steam trams in Sydney|Sydney steam tram]] <br> 0-4-0 || Hauling 3 trailers
| |
| |-
| |
| | {{railgauge|610}} || {{convert|21.2|m|ft|abbr=on}} || [[Darjeeling Himalayan Railway]] || The sharpest curves were originally {{convert|13.7|m|ft|0|abbr=on}} <ref>
| |
| Trains: The Early Years, page 51, H. F. Ullmann,Getty Images, ISBN 978-3833-16183-4</ref>
| |
| |-
| |
| | {{railgauge|610}} || {{convert|18.25|m|ft|abbr=on}} || [[Matheran Hill Railway]] || 1 in 20 (5%); {{convert|8|km/h|mph|0|abbr=on|disp=or}} on curve; {{convert|20|km/h|mph|0|abbr=on|disp=or}} on straight
| |
| |-
| |
| | {{railgauge|1495}} || {{convert|10.973|m|ft|abbr=on}} || [[Toronto Streetcar System]] ||
| |
| |-
| |
| | {{railgauge|1067}} || {{convert|10.67|m|ft|0|abbr=on}} || [[Taunton Tramway]] ||
| |
| |-
| |
| | {{railgauge|1435}} || {{convert|10.058|m|ft|abbr=on}} || [[Green Line (MBTA)|Boston Green Line]] ||
| |
| |-
| |
| | {{railgauge|610}} || {{convert|4.9|m|ft|abbr=on}} || [[Chicago Tunnel Company]] || {{convert|6.1|m|ft|abbr=on}} in [[grand union]]s.
| |
| |-
| |
| | {{railgauge|1676}} || {{convert|175|m|ft|abbr=on}} || [[Indian Railways]] || [[the sharpest curve permitted on Broad Gauge]]
| |
| |-
| |
| | {{railgauge|62.5}} || {{convert|28|ft|m|3|abbr=on}} in yard,<br> {{convert|50|ft|m|3|abbr=on}} elsewhere<ref>[http://www.lightrailnow.org/features/f_lrt_2007-02a.htm Lightrail now] New Orleans RTA/Brookville streetcar</ref>||[[Streetcars in New Orleans]] ||
| |
| |}
| |
| | |
| == See also ==
| |
| {{multicol}}
| |
| * [[:Category:Articulated locomotives]]
| |
| * [[Degree of curvature]], civil engineering
| |
| * [[Heaviest trains]]
| |
| {{multicol-break}}
| |
| * [[Lateral motion device]]
| |
| * [[Longest trains]]
| |
| * [[Matheran Hill Railway]]
| |
| {{multicol-break}}
| |
| * [[Radius of curvature (applications)]]
| |
| * [[Railway systems engineering]]
| |
| * [[Track transition curve]]
| |
| * [[Turning radius]]
| |
| {{multicol-end}}
| |
| | |
| == References ==
| |
| {{reflist}}
| |
| | |
| {{Rail tracks}}
| |
| {{Railway track layouts}}
| |
| | |
| [[Category:Track geometry]]
| |
If you are looking for a specific plugin, then you can just search for the name of the plugin. Good luck on continue learning how to make a wordpress website. This CMS has great flexibility to adapt various extensions and add-ons. When you loved this informative article and you would want to receive more details concerning backup plugin kindly visit our own internet site. Out of the various designs of photography identified these days, sports photography is preferred most, probably for the enjoyment and enjoyment associated with it. In the most current edition you can customize your retailer layout and display hues and fonts similar to your site or blog.
Right starting from social media support to search engine optimization, such plugins are easily available within the Word - Press open source platform. The higher your blog ranks on search engines, the more likely people will find your online marketing site. We also help to integrate various plug-ins to expand the functionalities of the web application. Furthermore, with the launch of Windows 7 Phone is the smart phone market nascent App. Once you've installed the program you can quickly begin by adding content and editing it with features such as bullet pointing, text alignment and effects without having to do all the coding yourself.
Minor and medium sized corporations also have a lot to obtain by shelling out in a very good website. Note: at a first glance WP Mobile Pro themes do not appear to be glamorous or fancy. I've applied numerous Search engine optimization-ready Word - Press themes and I can say from knowledge that I consider the Genesis Search engine marketing panel one particular of the simplest to use. These frequent updates have created menace in the task of optimization. After that the developer adds the unordered list for navigations.
Google Maps Excellent navigation feature with Google Maps and latitude, for letting people who have access to your account Latitude know exactly where you are. The SEOPressor Word - Press SEO Plugin works by analysing each page and post against your chosen keyword (or keyword phrase) and giving a score, with instructions on how to improve it. Specialty about our themes are that they are easy to load, compatible with latest wordpress version and are also SEO friendly. Can you imagine where you would be now if someone in your family bought an original painting from van Gogh during his lifetime. Wordpress template is loaded with lots of prototype that unite graphic features and content area.
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