Emergency Braking System for Trains

What about the cars behind the locomotive?

A freight train can weigh 20,000 tons. Water won't do much to slow it down.

After working in a rail yard for near 2 years fueling locomotives the guys there gave me a few crash courses on how modern diesel electric locomotives work.

The short version is whatever amount of HP they can produce to move the train they have of equal capacity to slow it down, plus a bit extra and that doesn't include any of the locomotives or rail cars mechanical brakes.

The theory of gradient climbing and descending, as was explained to me, is that they use the number locomotives needed to get up the slope +1 (or more if it a really steep mountain pass) so that even if one locomotive went down they still have enough power to get up plus enough braking capacity to get down without using the mechanical brakes.

Or that's the theory anyway.

I went to Mesula MT last year and part of the interstate runs through the same pass as the rial lines and I saw one grain train that had at least 10 locomotives spread out through it from end to end. Guessing that between the steep ascents and descents they felt that was at least how many they needed to keep things under control.

'whatever amount of HP they can produce to move the train they have of equal capacity to slow it down'

You are confusing fossil fuel poweres trains with electric trains.

For electric trains, they should have about the same capacity to take energy from the grid (accelerating) and to return it to the grid (braking).

However, if you take the energy from a fuel, you do not have the capacity to make fuel out of nothing, do you?

Btw, it is called regenerative braking. CR4 has a few discussions abput it.

<...the regenerative power from braking gets dumped into a huge set of resistors and dissipated as heat...> is great for saving brake blocks and pads on long down-grades, though its performance is limited by the adhesion between locomotive wheels and the rails. In contrast, a modern fully-automatic train-length power braking system adds in the adhesive braking capacity of the train as well, leading to stronger deceleration than resistance braking on the locomotive alone. Further, automatic train-length power braking is almost a global standard these days.

BTW all locomotives in the US may use diesel fuel, but it is in turbine engines on many, and all use electric motors on drive wheels, and AFAICT all use dynamic braking these days. We are not stuck in the 19th Century over here, in spite of the Sergio Leone films.

Actually, we are still 19th century, especially in our railroads. Last century, when the Milwaukee road pushed out to the West coast they immediately electrified the mountainous region because traction motors are far more powerful and have much better braking force. They are also far cheaper to run than diesel or steam since most all of the electricity was hydro and electro-mechanical maintenance is nowhere near as complicated as steam or diesel. Of course as soon as the Milwaukee Road was bought out the new owners immediately went back to diesel, spent millions to remove all of the cantenary and electrical lines so that re electrifying it would now be prohibitively expensive.

The purpose of the water trough was to fill the water tanks in a steam locomotive. Not much braking there...

That is true, but in that case, the water in the trough is being directed into the tender (less resistance). My idea would be a barrier that hits the water, trying to push it away (greater resistance).

There would have to be a scoop on every car.

A train weighs much more than a rocket sled. Even if the water is in the place where you need it, all you will get is a big splash and the train will keep on going.

Exactly. To take a speeding 20,000 ton train down from 60 MPH to 30 MPH you essentially have to accelerate an equal 20,000 tons of water up from a stand still to 30 MPH or a proportionately similar ratio of mass to speed trade off by either moving more water mass to a lower velocity or less water mass to a higher one or by dissipating a specific amount of energy in the water mass while recycling it on the go somehow.

Same basic principle of a speeding bullets Foot/pound force value. What rate of velocity change do you want in what time and or distance frame and how do you dissipate the energy being transferred?

So what we really need is a momentum transfer device...

It would destroy the tracks, but what about having the last car/tractor drop anchor (hydraulically) to basically insert a chisel stinger about three-four feet deep in the ground? Surely, that would create some friction, and would certainly result in a lot of new hires working for the railroad in rebuilding tracks (over and over).

this idea is not only catastrophic for the rails but will not work as the force on the car connectors would be too high and they would fail, most likely at the nearest car to the "chisel stinger" at this connection would see the highest load. the result would be a train that is still moving AND the decoupling of the car would blow out the air pressure which applies force to the car brakes. and btw: a section of track will now need to be repaired from leveling out the gravel bed to replacing the railroad ties and track.

Yes, I knew this was a really "dirty" idea when I tossed it out there?

How about big Kevlar balloons that "pop" out on the lead loco, and "bounce" whatever is on the tracks to a safe location (moving bounce house style). OR large balloons that pop out (at randomly oriented) points on each car, and provide some serious air drag at first.

Or maybe, just maybe we edumacate these folksies that wantses to parksies on the tracksies, whenever they see a train coming?

I can even see something like a giant air bag set into the crossing, that pops the car off the tracks, then deflates again in time to safely allow train passage. The persons in the car will be injured, no doubt, at least not killed in high percentage.

I suspect that the loco did not loose much speed during this exercise. And of course a limitation is that the at-grade crossing would need to be on flat, level ground.

More importantly, train dynamics would probably prohibit this. Simply put, a train brakes on ALL its wagons' wheels during a stop. Locomotive brakes on their own are used very carefully (usually to do with "stretching" or "compressing" the train on undulating routes). If you suddenly put a massive braking force on the locos only, the coupler/buffer forces from the 10 000t+ of the following wagons would be prohibitive. The results would be either that the buffers will break where it attaches to the wagons, or that the train will buckle sort of concertina-style and derail. This is for freight trains. For passenger trains, a sudden brake effort would result in injuries or death of passengers, especially anyone standing at the time.

In addition to dynamic braking, I also employed the generous use of the Jake brake ( especially in those areas where there were signs posted that Jake brakes were prohibited ) even though the sounds would echo for miles around.

Don't we all?

Kinda make you wish railway locomotives had Jake Brakes too, doesn't it?

Interesting idea, how many G's? Anything over 2-3 G's expect passenger injuries?

Sorry, but I think this system is not going to work in all cases. If it picked up water and used the water (converted to steam by thermal dissipation of the braking system), to thrust backward (in tension at the final car/locomotive), that might be of some slight use.

The maximum deceleration for a regeneration, Metadyne or a friction braking system is limited by the coefficient of friction/adhesion between the wheel and the rail, typically in the 0.2 region for dry rails and somewhat less for wet ones. Of these, the Metadyne arrangement is the most effective, as it can operate at the limit of friction reliably, irrespective of rail condition; that is why London Underground prohibited its use in its Rule Book: it was extremely hazardous to standing passengers.

In your opinion would there ever be any worth to a system that enhanced friction through magnetic attraction of the wheels to the rail? Not sure it would work at any rate, but simple enough to test.

My unsolicited opinion is, it's not worth the bother.

The contact area of a typical locomotive wheel on a rail is the size of a dime and 600–800 MPa. pressure.

...but is a considered opinion, clearly worth as much as mine. Thanks, Lyn.

There is actually a mechanism that sprays sand between the rail and the wheel to increase traction. video shows this, fast forward to about the 2 min mark. i know they use this to start the rig and for momentum before approaching a steep grade but not sure if used to brake.

https://www.youtube.com/watch?v=bdLcipx37b8

Sanding has been used to increase adhesion for the thick end of 150 years. The emergency braking arrangements still depend upon the coefficient of friction between wheel and rail; sanding increases it.

yeaaa, implied..which is why i brought it up, but thanks for reiterating.

i love guys like you that repeat back what was just told to them, change the wording a bit and then act like they just made a profound statement.

Unfortunately CR4 does not have a 'Safe Space' room for you go to nor doe it hand out participation trophies for you having done anything at all here based on your standards of value alone.

One person comes up with a base idea and then someone else reiterates while expanding on it and then it passes the the next person who builds a bit more using largely the same process.

Get used to it. This is how people of engineering/technical mindsets tend to work when brainstorming/whimsically pondering on a subject.

252 mm/2

Trams do that.

OK, but on trams, isn't the speed slower in the first place, and the rider is on a cable, and the magnetics simply latch onto the cable with some pressure?

I am not educated at all on trams.

I am not talking about normal braking, but emergency braking. Increased friction is what will be doing all the work. An emergency stop for a train locks up the wheels (I believe), so friction against the rails is lost. That being the case, some other external form of resistance needs to come into play. The rocket sled idea prompts my emergency stop device. This idea was prompted by an increased incidence of train crashes at level crossings within city limits in my area of the state. Trains don't travel "full throttle" through the city, so a water braking device might work. I don't know all the science and technology that goes into such an idea, I'm just the idea man. I present the idea; you evaluate it. If you deem it a working idea, you can propose it and keep the profits from it.

The fastest to stop a train in an emergency situation is with another train.

In theory it would probably work rather well but in reality any open water source is going to attract animals and everything else you don't want on the tracks thus causing a lot of other issues with each water trough.

As tough as the front end of a locomotive is their windows and headlights don't hold up to birds and anything else any better than the ones on your vehicle do.

Then theirs the logistics of how much water you would need to bring the speed of a loaded train down. It's a lot to have concentrated between two tracks so it either has to be very deep or very long to work well!

Switching the train into a lake fulfils those criteria!

...yes, but think of all the drowning chickens! Save the chickens!

I liked your tram magnet sled idea a lot better.

Other issues are water supply logistics, evaporation, freezing and grades.

Better to grip the top part of the rail like a linear disc brake or use rubber opposing idler wheels with their own brakes.

I come up with another idea for stopping a train. Along the main thoroughfares in mountainous terrain, there are emergency turnoffs, called run-a-way lanes used by trucks when going down hill. The turnoffs are positioned part way down from the crest of the hill. When the truck driver realizes his brakes are failing, he can steer off onto the emergency turnoff. The turnoff leads to an area of soft sand which slows down the truck. Maybe a similar arrangement could be used to stop a train. The train would be diverted onto a spur which would begin to turn into an upgrade. The upgrade would increase progressively to a point where momentum would drop to zero. This could be called the "roller coaster" effect. The turnoff would be controlled remotely by sensors at the crossing and by the locomotive engineer. It could work, but it would take a few miles either side of a crossing to implement.

I don't know why they, in the U.S. don't use the crossing gate system used through Europe and Japan; a gate that completely isolates motor vehicles from the track. You have all seen it; drivers will go around the crossing gate because they don't see a train approaching. A couple of months ago, a tour bus loaded with senior citizens stalled at a crossing and was hit by a freight train; many deaths. This happened in Biloxi, Ms, a few miles away from where I call home. I'm sure these ideas have been brought up many times over and yet; things don't change. I am very conservative, but when it comes to technology, I'm very progressive,(non-politically speaking).

The idea has its merits, but acquiring the additional right-of-way, installing the upgrade (literal and figurative) would be very costly, and in crowded areas, or if train has sufficient momentum to overcome the final grade and launch over the end??

How about an automatic ramp for stalled traffic on the tracks. Hydraulic (fast system) literally takes whatever vehicle, and launches it on a down slope so that it can safely roll away. It could work in an isolated number of events, but would be no help at all in the event of a traffic backup, with one unlucky soul stuck on the tracks.

Smarter traffic control, bypass spurs, etc., might go a long way in this regard.

Once again, the five P's come into play. Especially when driving: Proper Planning Prevents Poor Performance.

It seems that sometimes the "smartest" people (that think they know better), are the ones that want to circumvent safety barriers, procedures, and warnings.

Making alert people on the roadways is good, and so are drug-free, alcohol-free ones.

How about at least putting up a train horn right at the crossing barrier - to make the trains sound like they are right there, and further discourage inching up, around, or through the barriers, or pulling up thinking traffic will move off ahead.

I think think the 5 P's have been changed.

1. Play dumb.

2. Pretend. (It wasn't you.)

3. Point blame. (It has to be someone else's fault.)

4. Pontificate. (Self justify actions, more absurd reasoning the better.)

5. Protest. (Claim unfairness/bias of the system when first 4 points fail.)

Then there is also the 6th P: Phart!

Did you copy that from the White house press site?

I love poking the bear on Fridays!

Did you know that Winnie the Pooh (short for Winnipeg) was an actual black bear from Canada rescued by a veterinarian soldier at the time of his transport to UK during WWI? He survived battle while the bear became the all-time favorite of the London zoo. It broke his heart to leave his bear behind again after the war, but greater love does those things.

An associate of his wrote the story of Winnie the Pooh for his son and his beloved stuffed bear, (named Winnie in honor of the London zoo bear).

No. It came from the "How to be a Modern Liberal" - for dummies handbook.

Rules of conduct section to be specific, and I believe clintons new book covers the applied theory of operations multiple times over.

If you don't have a copy of either it I know of at least one member here who can likely loan you either or both of his.

I thought that was the 6 p's.

Proper planning prevents piss poor planning.

Nah, the first six P's are just the preamble to the remaining 6 P's. Have a great weekend Tony!

How about this idea:

You got an electric garage door, it has sensors mounted on each side of the door opening, when an object interrupts the sensors, the garage door stops moving.

When a vehicle, in this case a bus, interrupts the sensors, an automatic device aboard the train activated the trains braking system.

Nothing is completely fool proof, no matter how much you try, you can't completely stop stupid.

One can stop stupid, one just can't fix stupid.

With the cow-catcher, at least this thing is a "toss-up".

I was really trying to read the last topic of Missile defence.

However it is blocked. Likely for all, or only for some?

Perhaps a moderator could elaborate. ?

Thank you.

I was easily able to navigate to it, but did not attempt posting again.

Track_Pans.pdf

The track pan Scooping water in the age of steam engines.

file///C:/Users/jajr/Documents/My Webs/JimQuest NEW/writ/trains/pan...

( The PDF file is 2 pages (a) & 15 pages (b) ( particular system configuration )

James Alexander JR.

The Kiesel water scoop patent 1894

A cheaper method would be to reinstall, " Pilots " on railway engines. This way when the train hit and object ( car ) (sic) the object would be tossed up out of the way and the train could continue on its way. In this manner, passengers & freight could keep their timetable .

Cowcatchers in another era. Maybe effective, but no guarantee on the final state of those plowed out of the way.

After all the discussion of past, current, and possible additional braking systems for trains, is there really that much of a problem with runaway trains and resulting crashes/fatalities that it is necessary to add more emergency braking capability? What's the ROI going to be? Will it really be worth it to spend whatever it takes to stop those few trains that conventional methods won't? I'm not hearing of large numbers of runaway train accidents these days - do we actually have a problem that needs solving here?

The level crossing is a nineteenth century solution to a 21st century problem. All newly-designed high speed lines in the UK are devoid of the crossing type by design, utilising over-bridges and underpasses instead, and it is extraordinarily difficult to achieve sanction to install a new level crossing on any other passenger line in the UK.

I suspect we have wild solutions in search of a problem, as is usual.