Train inspection system

Train Inspection Systems
There are several types of train inspection systems.

Inspections are made on the engines and the cars before the train ever starts on it's journey.
This is done by mechanical department workers and sometimes by cameras and scanners.
When the pre-trip work is done, the train is considered safe to move.
!!!need links and language for Federal Rail Administration rules for inspection here!!!
Once the movement is started the train encounters several types of in motion detectors.

• 
  A Hot bearing detector w/ dragging equipment unit

The technologies vary from a simplistic paddle and switch to inferred and laser scanning, and even
ultrasonic audio analysis. These are used to inspect trains, cars and the loads on them.

The systems on the US railways are in a dozen or so major groups listed below.
!!!Each of these need a page and link!!!

• Wheel Impact Load - high impact wheels have some defect where it does not roll smoothly down the track,
  

A flaw in a wheel causes vibrations or banging. This is very destructive to the track structure and the rolling stock( the cars)

• Weigh-in-Motion - Checks for overloads or shifted loads that can be dangerous
  

• Truck Hunting - looks for “hunting”, lateral movement in the gauge of the track.
  

• Truck Performance - stiff or poorly steering or axle sets that don't follow the path of the track correctly
  

• Acoustic Bearing Detectors- Listens with special microphones for internal bearing defects as the equipment moves past.
  

• Hot Wheel Temperature Detectors- Look for hot and cold wheel which are generally caused by braking equipment failures.
  

• Bearing Temperature Scanners– compares the heat generated by the bearing with set "Alarm limits" and then gives that information to the railroad. This data is used to detect failures and stop the movement before major damage occurs. When the bearing overheats it is called a [Hot Box]
  

• Dragging equipment Detectors- Do just what the name suggests, they are able to detect things hanging or dragging under the cars.
  
• high / wide sensors - These are able to measure the height and width of railroad stock so that things that won't fit under bridges and through tunnels are stopped.
  
• Slide Fences- A slide fence will detect falling rock and other types of debris on the right of way.
  

• Wheel Profile - flange and tread measurements
  

References

{http://www.aar.com/wdprc/ Association of American Railroads}

{http://www.aar.org/~/media/aar/backgroundpapers/high-techadvancesimprovesafetyandefficiency.ashx Association of American Railroads}
{http://www.progressiverailroading.com/news/article.asp?id=2696 Progressive Railroading}

External links

Southern Tech