DRAFT: This module has unpublished changes.

1.  In the crashes we saw from the video, we learned that due to the complexity of trains, even when one small thing goes wrong, it can spiral into a disaster. In places that had more than one direction for a train to go, they had a mechanism that required people to move a lever to live up the tracks with the corresponding trail. This specific disaster was not necessarily due to complexity, but human factors. This incident occurred because of workers that did not notice that the pin that kept the lever from switching between sides was missing. This seemed weird that they would not have fixed it or reported that something was wrong with it. Without the pin, the lever should be able to freely, and easily move because it has nothing stopping it from moving. Another disaster that was a result largely of human error was a collision in Kew Gardens involving 2 trains. While one train was stopped to get fixed, another train was traveling towards it. The reasons that the trains swiped each other was because of the brakeman, who’s job it was to show incoming trains that they needed to wait before they could continue going. They had stopped their warnings too late and the incoming train did not see a warning, as well as saw an “All Clear” which they assumed was for them. It was for the train that had a brake problem and the trains ended up sideswiping. A modern feature that has improved railroad reliability are axel counters. These are sensors that monitor the speed, and direction that a train is heading. It can also be used to see if a train passed through or is stuck and did not pass through. This would show that the train was stuck, and that the area was not clear for a second train to try to pass through.


2. When an engineered system is complex, it can be able to accomplish many tasks. The bad thing however, is when a small component breaks, it can lead to many other things failing. This becomes especially apparent in extreme conditions like hurricanes, tsunamis, and other such natural disasters.  One example of this are the levee’s in New Orleans during hurricane Katrina. The levee’s in New Orleans were designed like an “I” in that they were just a vertical concrete in the ground. Just by looking at how the design the I beam looks like it would easily come out of the ground when a heavily storm happens. They chose this design because it was cheaper compared to the T beams. Another thing that also helped aid in the destruction of the levees was that they had a relatively low factor of safety. And to make it even worse, the strength of the soil that the levees were on was thought to be stronger than it was. Both the shape of the beam, and the low safety factor are from the normalization of deviance. The engineers designed the beams to be both cheap, and with the minimum allowed safety. These made it so that once water got in between the wall and the soil, the wall would easily tip over. These conditions, while being very unlikely, should still be considered especially when the areas being affected is near the coast and is affected by hurricanes a lot.




3. The location that the system is placed in is one of the most important things. It shows up what the weather is likely to be like in a certain area. For example, if we suggested an engineered system to somewhere like New Orleans, we would have to make sure that the systems that we do put in place, will be able to withstand the weather. This means that we would need to have something that will be able to help mitigate flooding and hurricanes. But if we made it somewhere in land, we would be able to prioritize on earthquakes. One example of a real system is the system that New Orleans have made since their recovery from hurricane Katrina. After Katrina, they learned what systems failed and which systems should be implemented so that in the case that an event this catastrophic happens, it would be as confined as possible. Since then, they have made higher, more resistant levees and flood walls, installed emergency pumps, and the pumps were redesigned so that they are able to withstand flooding heights in 100-year and 500-year events. While their system has not been tested to the degree that it was during hurricane Katrina, but from the changes in the systems that have failed, the complexity of the systems does not increase that much more. According to this website, these changes, the risk and potential loss of life could be decreased by 75%.      


Another example are bridges in areas that experience major earthquakes. There can be places like San Francisco, Tokyo, and Istanbul. California has had a decent amount of bridge failures due to the frequency of them.  In 2005, engineers were able to test a seven-story building to see if it would be able to withstand an earthquake with a magnitude of 6.7.


Another way that engineers are trying to reduce the risk of natural disasters, are by finding new ways to absorb the impact of the earthquakes by making it flexible. Using new materials, the newly made bridge would possibly withstand an earthquake of 7.5. The structure is made of vertical rods that are reinforced by a metal alloy. This would allow the metal to bend but be able to return to it’s original shape. The downside to this is that the materials are 90 times more expensive than the concrete and steel used in other bridges. This would be a great change in bridges because many bridges that currently exist are vulnerable to earthquakes. If this material can be produced and at a cheaper price, it would be able to change the way bridges were constructed all over the world. The material would be able to reduce the number of bridge collapses. However, this material, if only included in certain parts of a bridge, might introduce more complexity to it. With the addition of it, you would have different kinds of metal and concrete reacting with each other.


DRAFT: This module has unpublished changes.