Level junction
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A level junction (or in the
The cross-over structure is sometimes called a diamond junction or diamond crossing in reference to the diamond-shaped center. The two tracks need not necessarily be of the same
The opposite of a level junction is a flying junction, where individual tracks rise or fall to pass over or under other tracks.
Risks
Conflicting routes must be controlled by interlocked signals to prevent collisions.
Level junctions, particularly those of fine angles or near right angles, create derailment risks and impose speed restrictions. The former can occur as the flanges of the wheels are momentarily unsupported and unguided and can slip through the gaps in the rails, and the latter because the assembly contains elements that can break or vibrate loose.
Level junctions are considered a maintenance issue by railroad companies as the inherent gaps tend to be hard on locomotive and rolling stock wheelsets. Switched diamonds partially solve these problems, but introduce new ones.
Examples
Flat crossings are particularly common in the United States where the lines of one company cross the lines of another company, and there is no particular need for the lines to be connected for through traffic.
Three examples of two tracks crossing another two tracks:
- At Rochelle Railroad Park in the United States, the double track Union Pacific Railroad main line crosses the double track BNSF Railway main line forming four diamond crossings altogether at this location.
- At Nagpur, India. Nagpur is where trunk railway lines running from Kolkata in the Eastern end of India to Mumbai in the Western end, and the one from Delhi in the Northern end to Chennai and other places in the southern end cross. Nagpur in fact is the geographical Centre of the Indian subcontinent. The double lines crossing from the North to the South and those from East to West form a set of four diamonds. This type is also called as "True Diamond Crossing".
- At Nottingham to Lincoln Linecross. This is the fastest flat-crossing in the UK, with trains travelling north-south allowed to cross the junction at 100 mph (160 km/h). Protection of the junction is controlled by signalling.
- Grafton, Ohio SR57 at Cleveland St
Local transport
Flat crossings appear in some urban passenger rail systems, which can cause delays at peak hours as a train heading in one direction may have to wait for trains heading in another direction to clear the junction before it can cross. The junctions leading onto and off from the Loop of the
Level junctions are often found on
Different gauges
A
At
In
In
In
Drawbridge crossing
In
See also
- Diamond crossing
- Double junction
- Junction (rail)
References
- ^ "Google Maps". Google Maps.
- ^ Glyn Williams, Tourist and Enthusiast Railways, Wales. Retrieved 2008-03-21.
- ^ "Philadelphia Transit; Streetcars;Route 11 (Kavanaugh Transit Systems)". ktransit.com.
- ^ Angie Gustafson; Carrie Gregory; Karen J. Weitze (2001). "Western Salt Company Works" (PDF). Historic American Landscapes Survey. Library of Congress. Retrieved 29 April 2015.
- ^ "Sugar Cane Railway Drawbridges and Catch-points Photos and Information". www.sa-transport.co.za.
External links
Media related to Diamond crossings at Wikimedia Commons