# How many miles to stop a long, loaded, 50 MPH freight train? **URL:** \ **Category:** Factual Questions\ **Created:** [March 3, 2021, 6:09am UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166 "2021-03-03T06:09:49Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Bullitt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bullitt/32/5725_2.png) [@Bullitt](https://boards.straightdope.com/u/Bullitt)\ **Post date:** [March 3, 2021, 6:09am UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/1 "2021-03-03T06:09:49Z")
Yes I realize many factors affect the answer, including coefficient of static friction, train mass and speed, track incline, and whatnot. I’m simply looking for a rough order-of-magnitude answer to the question, for a loaded freight train of, say, 100 cars on a flat track and going at 50 MPH, when max emergency braking is applied, how many miles before that train stops? Is it 1 mile? 10 miles? 100 miles? My guess is that it’s somewhere between 1 and 10. ---
**Author:** ![gnarator](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gnarator/32/8266_2.png) [@gnarator](https://boards.straightdope.com/u/gnarator)\ **Post date:** [March 3, 2021, 6:14am UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/2 "2021-03-03T06:14:12Z")
Closer to a mile than 10 miles. Per [Operation Lifesaver](https://www.minnesotasafetycouncil.org/ol/stop.cfm#:~:text=Trains%20can't%20stop%20quickly,fully%20applies%20the%20emergency%20brake.), it can take a mile or more for a freight train moving at 55 mph to stop. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [March 3, 2021, 4:11pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/3 "2021-03-03T16:11:33Z")
For what it’s worth, I recently learned that a fully loaded boxcar or hopper can weigh as much as 220, 000 pounds. ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [March 3, 2021, 5:26pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/4 "2021-03-03T17:26:22Z")
Here’s a relevant thread: > **[Stopping Distance equation?](https://www.trainorders.com/discussion/read.php?1,124516)** > > A few months ago someone here had a "seat of pants" stopping distance formula -- (It was something like; total length divided by speed) Does anyone remember that string or have that 'equation'? Thanks Tim G over ---
**Author:** ![Bullitt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bullitt/32/5725_2.png) [@Bullitt](https://boards.straightdope.com/u/Bullitt)\ **Post date:** [March 3, 2021, 7:47pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/5 "2021-03-03T19:47:44Z")
> [@PastTense](#): > > Here’s a relevant thread: > > [Stopping Distance equation?](https://www.trainorders.com/discussion/read.php?1,124516) Thank you. That was helpful. ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [March 3, 2021, 9:13pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/6 "2021-03-03T21:13:49Z")
Does the number of cars in the train make a difference? All of the wheels have brakes, don’t they; so if each car is capable of stopping itself does coupling a hundred of them together change the stopping distance? ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [March 3, 2021, 9:17pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/7 "2021-03-03T21:17:06Z")
Does it matter if the train is fully loaded or not ? I mean the force of friction is directly proportional to the weight, so effectively the weight will cancel out when looking at deceleration (?) ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 3, 2021, 10:20pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/8 "2021-03-03T22:20:45Z")
It might be up to the brakes rather than wheel traction on the rails. If the brakes have limited clamping force, or limited heat dissipation capacity, then the total weight of the train may affect stopping distance. ---
**Author:** ![Bullitt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bullitt/32/5725_2.png) [@Bullitt](https://boards.straightdope.com/u/Bullitt)\ **Post date:** [March 6, 2021, 3:51pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/9 "2021-03-06T15:51:11Z")
So to explain… no, there is too much, let me sum up: To answer the OP, depending on many factors, it can take up to approximately a mile, maybe a bit more, for a fully loaded freight train of, say, 100 cars on a flat track and going at 50 MPH, when max emergency braking is applied. It would definitely be stopped before 2 miles. Fair enough? ---
**Author:** ![Yelnick\_McWawa](https://avatars.discourse-cdn.com/v4/letter/y/839c29/32.png) [@Yelnick\_McWawa](https://boards.straightdope.com/u/Yelnick_McWawa)\ **Post date:** [March 7, 2021, 3:33pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/10 "2021-03-07T15:33:34Z")
There’s YouTube clip of a freight train going 28 MPH when the emergency brake is applied. It takes 36 seconds to come to a halt. Using extrapolation, at 50 MPH (73.3 feet per second) it would take 64 seconds to come to a halt. 64 seconds at an average speed ot 36.6 feet per second, that’s 2360 feet, or 0.45 miles. ---
**Author:** ![Q.Q.Switcheroo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/q.q.switcheroo/32/5713_2.png) [@Q.Q.Switcheroo](https://boards.straightdope.com/u/Q.Q.Switcheroo)\ **Post date:** [March 7, 2021, 3:44pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/11 "2021-03-07T15:44:51Z")
Need answer fast? ---
**Author:** ![Didi44](https://avatars.discourse-cdn.com/v4/letter/d/e47c2d/32.png) [@Didi44](https://boards.straightdope.com/u/Didi44)\ **Post date:** [March 7, 2021, 9:36pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/12 "2021-03-07T21:36:18Z")
Wouldn’t the possibility of derailing and jackknifing the trailer cars factor into braking force? The brake force of all 100 cars is unlikely to equal so I would think there would have to be sort of anti-lock pumping of the brakes. ---
**Author:** ![EdelweissPirate](https://avatars.discourse-cdn.com/v4/letter/e/8491ac/32.png) [@EdelweissPirate](https://boards.straightdope.com/u/EdelweissPirate)\ **Post date:** [March 7, 2021, 10:51pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/13 "2021-03-07T22:51:48Z")
> [@Yelnick\_McWawa](#): > > There’s YouTube clip of a freight train going 28 MPH when the emergency brake is applied. It takes 36 seconds to come to a halt. Using extrapolation, at 50 MPH (73.3 feet per second) it would take 64 seconds to come to a halt. 64 seconds at an average speed ot 36.6 feet per second, that’s 2360 feet, or 0.45 miles. Looking at your math, it seems you’ve assumed a linear relationship between speed and stopping distance. It turns out that stopping distance isn’t linear with speed but proportional to the _square_ of v0 . > **[the\_dangers\_of\_speeding.pdf](https://arconforensics.com/system/ckeditor/attachment_files/184/the_dangers_of_speeding.pdf)** > > 285.27 KB ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [March 8, 2021, 12:22am UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/14 "2021-03-08T00:22:39Z")
I don’t think doubling the distance is correct. Energy goes up with the square of velocity so I think quadrupling the distance would be more accurate. ---
**Author:** ![Yelnick\_McWawa](https://avatars.discourse-cdn.com/v4/letter/y/839c29/32.png) [@Yelnick\_McWawa](https://boards.straightdope.com/u/Yelnick_McWawa)\ **Post date:** [March 8, 2021, 3:27pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/15 "2021-03-08T15:27:35Z")
> [@EdelweissPirate](#): > > Looking at your math, it seems you’ve assumed a linear relationship between speed and stopping distance. It turns out that stopping distance isn’t linear with speed but proportional to the _square_ of v0 . No. My linear relationship is between speed and stopping time (not stopping distance). If you double the speed, you double the time to stop. You also double the average speed so the distance is quadrupled. ---
**Author:** ![Shoeless](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/shoeless/32/7099_2.png) [@Shoeless](https://boards.straightdope.com/u/Shoeless)\ **Post date:** [April 1, 2021, 1:16pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/16 "2021-04-01T13:16:28Z")
Not sure if this is any help, but there was a story in the Kansas City Star this morning about a BNSF freight train colliding with a car at a railroad crossing. While the story doesn’t mention how long the train was or how fast it was going, it did mention that the car was pushed for about half a mile before the train came to a stop. (I’d post a link but they don’t seem to copy/paste very well from the newspaper’s phone app.) ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [April 1, 2021, 1:54pm UTC](https://boards.straightdope.com/t/how-many-miles-to-stop-a-long-loaded-50-mph-freight-train/934166/17 "2021-04-01T13:54:17Z")
> [@Shoeless](#): > > Not sure if this is any help, but there was a story in the Kansas City Star this morning about a BNSF freight train colliding with a car at a railroad crossing. While the story doesn’t mention how long the train was or how fast it was going, it did mention that the car was pushed for about half a mile before the train came to a stop. Google says a train can weigh any where from 3000-18,000 tons. A mid-size car is about 2 tons, so you can assume the frictional drag of pushing one down the tracks is (at worst) about 2 tons. So the added deceleration, measured in G, would range from 2/18,000 to 2/3000, almost nothing compared to what the train’s own brakes are doing.