Train inspection system

There are several types of train inspection systems.

Safety is of high importance when train cars move across the rails. The cars are heavy and have moving parts that can break or become defective. Worn or broken parts can drag, pound, and generally destroy the cars and the track structure they run on. Quality inspections are needed not just before a car is moved, but also as it travels to it's destination. Inspections start 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. Many items are certified good to go, things like the braking system, the air, communication, and many more. Very much like the checklist an airline might use. When the pre-trip work is done, the train is considered safe to move. Once the movement is started the train continues to be watched by the employees and a host of scanners and monitors. These are sometimes called "in motion defect 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 devises are used to inspect engines, cars and the loads on them.

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

Hot Box & Hot Wheel Detection System PHOENIX MB (SST Signal & System Technik GmbH)

• (WILD) Wheel Impact Load Detector- 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”, A lateral movement in the gauge of the track, like drifting back and forth in a lane of traffic.

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

Sensors for a railway wheel impact load monitor - Lara, Victoria,

• Acoustic Bearing Detectors- Listens with special microphones for internal bearing defects as the equipment moves across the detector. These are very sensitive and can detect problems before the bearing reaches failure.

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

• Bearing Temperature Scanners– This type of defect watches each wheel bearing and takes it's temperature, then compares the heat generated by the bearing with preset "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 defect detector

• 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.[Structure gauge][Loading gauge]

• Slide Fences- A slide fence will detect falling rock and other types of debris on the right of way.

• Wheel Profile - These laser scanning devices make flange and tread measurements, comparing what it sees to acceptable dimensions.

• Trend monitoring systems(back office systems)- These systems are predictive, finding equipment problems as they start to develop.

External links

Southern Tech

{http://www.progressiverailroading.com/news/article.asp?id=2696 Progressive Railroading}

{http://www3.ntsb.gov/events/symp_rec/proceedings/authors/lechowicz.htm International Symposium on Transportation Recorders }

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