chitoryu12 posted:

The average freight train moving at 55 miles per hour or a passenger train at 80 miles per hour takes about a mile to stop. Trains have an insane amount of momentum and train operators have to be thinking miles ahead to effectively control their speed.

If a typical train driver sees an obstruction a mile away with binoculars, they usually have to resign themselves to hitting it.

B4Ctom1 posted:

Pretty much this. It is hard to explain not just the physics, but the amounts of forces involved.

We use throttle to create stretching or "draft" forces and dynamic braking (think of downhill engine braking in a car) to create bunching or "buff" forces.

To start with, when you are running the train, you are feathering the throttle or dynamic braking to keep "in train forces" at acceptable levels. This is based upon the terrain each part of the train is passing over.

Even small changes in grade, if there are enough of them under the length of the train, are enough to break knuckles, rip out draw bars, or derail cars simply by doing "nothing at all" at the wrong time.

In these situations heavier applications of power or dynamic brake are required to keep these "in train forces" down.

Think of a large sliced loaf of bread. I take the wrapper off of it and ask you to carry it across the room. One hand on each end should suffice. A small amount of pressure to keep the bread from being crushed and across the room you go.

The knuckle and drawbar connections between the cars seem very strong to the layman, but when compared to the amount of weight of loaded freight cars, and all of the cars behind them piled upon it, it may as well be dental floss.

You can break dental floss easily, but the difference is that it is hard to "crush" dental floss.

The poster I have quoted above is addressing something we call "train make up". THe "in train forces" can be additionally effected by the way cars or groups of cars are placed in the train. Long cars next to short cars, loads next to empties.

Generally freight trains that are not hauling a bulk of the same commodity are mixed freight. A bulk commodity train would be an entire train of wheat or coal. These trains are very heavy, and have their own set of problems, but in general do not have any issue of train make up because all of the cars are generally the same weight and type. Mixed freight trains are the most common types of trains on the main rail thoroughfares.

A mixed freight train I haul might have 25 heavy loaded lumber cars, 15 empty or loaded auto racks, 20 empty or loaded tank cars of various lengths, 30 empty or loaded covered hopper cars of various lengths, and 30 loaded or empty boxcars of two different lengths.

So for this example train of 120 cars. Lets say it weighs 7900 tons and is 9000 feet (2.75KM) long.

I am traveling along at 50 MPH.

The "head end" of the train has passed the bottom of the grade and the train is still descending the grade. As about half of the train leaves the grade I am looking ahead at the next grade to climb directly ahead. I have been using dynamic brake and need to "transition" from braking to power. I move the lever into the idle position and begin waiting my 10 seconds. In my my mind, from experience, I know that I need to rapidly, but gently begin notching through my power notches without allowing my train to accelerate past 50 MPH which I am restricted to.

The very head of the train is traveling around a slight curvature in the track. I also need to see that the next signal is green "clear" so that I do not have to formulate an entire other plan as a reduction of speed might be required instead. I see that the signal is flashing yellow "advanced approach". This will mean a reduction of speed to 40 MPH and a possible stop short of the second signal ahead.

As I am thinking of what I am to do next and waiting for the 10 seconds to pass, the next crossing becomes visible and I see that there is a truck hauling a low slung trailer with a heavy piece of equipment on it. He is blocking the crossing because his low slung trailer is stuck on the raised rail and crossing lumber that you drive across.

Without hesitation or further consideration, I slam the brake handle into the emergency position, dumping all the trainline air. I reach up and toggle the switch that ensures that the "End Of Train" device dumps from the rear as well. I bail off the locomotive air brakes because they are so powerful in a situation like this, that they can cause such a massive buff forces which will certainly derail a train. Additionally they can crumple or destroy the track beneath them.

While in earlier transition from dynamic braking to power "slack" had developed in the train. Slack is neither draft or buff, but more of a null position like rail cars standing in a yard not connected to a train. A developed space between cars where they are sort of relaxed.

As the air dumped from the train-line, the brake valves on each car sense this emergency and dump the full value of air contained within their emergency reservoir into the large cylinder that applies the brakes giving each car higher than usual stopping power.

Somewhere near the head end of the train a group of empty tank cars having such massive braking power begin to stop the train, but right behind them a group of heavy loaded hoppers presses against them, their own braking being less substantial. A tank car of Anhydrous Ammonia right between the groups which has been taking the brunt of these two opposing forces has a wheel that lifts off the rail as it is being pressed around a curve. This car, the car ahead of it, and nine of the loaded hopper cars behind it all leave the rail and head into a tiny quiet suburb in the middle of the night.

Half way back in the train where the most of the box cars are, they settle down for their stop. Still bunched because they were still descending the hill. The heavy loads of lumber fighting them as they come to a stop. Even though on straight track the, one end of an empty boxcar in the group begins to lift into the air. The opposing force of the heavy lumber cars and the stopping train ahead of it is too much. As it sets back down the wheels miss the track and begin to erase the track, all of the cars behind it having no track to ride on begin to take paths of their own in each direction.

Near the back of the train the auto-rack settle down hard. Harder than the group of heavy lumber cars ahead of them. This causes one of the long 500+ pound (230kg) draw-bars in the third auto-rack to be sheared from place. For a moment it tumbles through space, whistling though the wind in contact with only the air. Then it strikes a tie and the car passing above it in vaulted, only inches off of the rail, and a carload of new rangerovers tumbles end over end into a reservoir of drinking water.

The drawbar is angry, propelled by its last impact it drops onto the rail for a moment derailing a load of mini coopers, a load of corvettes, a load of ford diesel pickups, and a load of prius. The last of the autoracks ram into those derailed and the drawbar impales itself through the bottom of a boxcar piercing 20 cases of aged Glenfiddich.

Back on the locomotive, pressed forward by the loads behind, we cover the half mile to the stuck trailer in about 45 seconds. My conductor sees that the piece of equipment is a D9 Caterpillar bulldozer and screams like a woman as he jumps from his window at 35 mph. The fall from 15 feet in the air certainly would have killed him but instead he tumbled and struck feet first shattering his legs in 20 places and cartwheeling to his death as his head exploded when it struck the hard granite ballast some 20 times or so in the cartwheeling tumble. It takes 24 hours for them to find his body under crumpled boxcars.

I run out the back door to the second locomotive where I lay down in the cab. The impact at 35 mph is brutal. The second locomotive which I am on climbs under the front locomotive. The third locomotive does the same to mine. When the locomotive comes to a rest, is on its side, and both my arms are broken.

I drown, face down, in 200 gallons of brownish, blueish sewage from a chemical toilet long overdue for a cleaning. But my dignity is preserved because a fire from the combined 12,000 gallons (45.5 Kiloliters) of fuel burns for 3 days incinerating me and most of the locomotives completely.

The undocumented worker driving the truck with the wedged trailer disappears.

During the conductor's autopsy, trace amounts of THC from a brownie he consumed 3 weeks earlier while on vacation in Amsterdam are found to be the cause of the accident.

It was also noted in the government report that the cellphone of an engineer on a different train following ours was "on" at the time of our impact, and this may have contributed to the wreck.

Devor posted:

After exactly one accident of this type, the city/county, and railroad should have been demanding that the traffic stuck where that guy was, get cleared by the signal every time a train came through there

"Hey Bob, what happens if someone 'blocks the box' at this intersection, when a train comes through?"

"Uh, I guess the train hits them, Jim"

"Maybe we should make it so that doesn't happen"

"That sounds complicated, let's just have accidents a few times a year"

Memento posted:

https://i.imgur.com/CHSTUPp.mp4

Flash Gordon Ramsay posted:

I've seen that train post before, and it's pretty enlightening, but what's the value in making an illegal immigrant the cause of all of that in his hypothetical?

Flash Gordon Ramsay posted:

I've seen that train post before, and it's pretty enlightening, but what's the value in making an illegal immigrant the cause of all of that in his hypothetical?

Space Jam posted:

lost another at the plant today. had a foreman playing hacky sack with another floor worker above the iron smelter and lost his balance and fell over the rail. he landed next to the pot luckily but the weight of him falling off shook the walkway (suspended with wire ties to the connecting joints to save money) and the other guy dropped his slurpee into the molten iron and the foreman took a splash of liquid metal to the face. goddamn hippie.

Sagebrush posted:

Riveting

DiHK posted:

That's what I want in a Thomas the train episode.

Mr. Apollo posted:

I like the guy at the end walking up and putting out the caution sign.

https://i.imgur.com/DIRSSBo.mp4

quote:

A downburst is created by a column of sinking air that after hitting ground level, spreads out in all directions and is capable of producing damaging straight-line winds of over 240 km/h (150 mph), often producing damage similar to, but distinguishable from, that caused by tornadoes. This is because the physical properties of a downburst are completely different from those of a tornado. Downburst damage will radiate from a central point as the descending column spreads out when hitting the surface, whereas tornado damage tends towards convergent damage consistent with rotating winds.

Bad Munki posted:

The video source with all the scraping and whatnot is so great.

https://www.youtube.com/watch?v=NnnkzsByKzY

Croatoan posted:

There's no wheels on what was the bottom

Mammal Sauce posted:

Sorry if this is some sort of language-barrier issue, but... :

The Bloop posted:

Bought the extra insurance so I'm 100% covered

gently caress IT

Kibayasu posted:

I wouldn't be surprised at all if this was a "gently caress uhaul" situation.

Mammal Sauce posted:

Sorry if this is some sort of language-barrier issue, but... :

Mr. Apollo posted:

I like the guy at the end walking up and putting out the caution sign.

https://i.imgur.com/DIRSSBo.mp4

GotLag posted:

That's an oddly specialised attachment

Mr. Apollo posted:

https://i.imgur.com/DIRSSBo.mp4

bloom posted: