Let’s start with dragging load detectors…
I’m pretty sure detectors gat placed to protect long high bridges but where else are they found please?
Are they out in the wilds or found in cities?
My trackplan has a diamond for two seperate RRs to cross. Is this a likely place for protection (on one or both roads) by a dragging load detector? Would there be a detector on eacg side if the diamond?
What (if any) other detectors appear in town please?
Thanks
[:P]
google is your friend, enter “railroad detector”. wikapedia site has some info and photos.
grizlump
Dragging equipment detectors (DED). The only way the “load” is dragging is if the floor of the car collapsed. Most of the time its brake rigging or a derailed wheel.
Maybe, maybe not. Most DED’s are combined with hotbox detectors and are placed about every 20-30 miles along the railroad.
Every 20-30 miles. Wherever that ends up.
There normally wouldn’t be a DED by the diamond, unless it just happened to be located about 20-30 miles from a yard or another DED.
There aren’t “town” detectors or “country” detectors. How many people live near the tracks has no bearing on it.
There are dragging equipment detectors, hot box detectors, wheel impact detectors, and wide load detectors (short of through truss or girder bridges, tunnels or overpasses). The first 3 are often combined. Wheel impact detectors are fairly rare.
Would they be placed after a switch yard, or other areas that are more likely to have derailments?
Hi, Dragging equipment detectors are used to test to see if anything is dragging below railhead level. Could be air hoses, a piece of a car, anything. Anything dragging can cause a derailment, snagging a switchpoint, etc. They are used everywhere, not just at bridges. How far they are apart depends alot on the terrain, and where visibility of the train from the locomotive is limited. Norfolk Southern, in the Alleghenies for instance, has detectors every 5 miles or so. After cabooses and towers disappeared, machines have to replace human eyes that are no longer watching the train for defects. Here in the northeast, where ice and snow can build up, “fingers” are placed on either side of the detector so that icicles are knocked off so that they will not trigger a false reading.
Hot box detectors look for hot wheels / wheel bearings. Hot boxes are rare with most equipment being roller-bearing equipped now, but a sticking brake / hand brake left on can heat up a wheel so much that it can actually become loose from the axle. Most hotbox detectors these days are incorporated with dragging equipment detectors. Detectors alert train crews to problems by calling out on the radio over the regular road frequency “defect found” and it announces the number of the axle from the front of the lead locomotive where the defect is. Example: a train with a single 4 axle diesel and 4 cars. If you have a defect on axle #7, the defect is on the 3rd axle of the first car of the train.
If a detector goes off, the crew stops the train and walks back to the axle where the detector has picked up the defect. If a defect is indeed found the crew will make a determination as to whether they can repair the car or whether it is better to set out the defective car at the next available siding that can hold the car. If a setout is required, the train will operate at rest
As Dave H noted, Dragging Equipment Detectors (DED) and Hot Box Detectors (HBD), are normally combined and located every 20-30 miles, city or country. High Car and Wide Load detectors are normally located sufficiently in advance of a restriction to protect it. Though, still not terribly common, Wheel Impact Load Detectors (WILD) detect wheel anomalies, like flat spots and built up tread.
Nick