In response to 'why can't passengers know the speed?'

[PerRock]

A lot of modern trains have that information available to the passengers. Usually it's presented with other route information in either an LCD screen or an LED scrolling bar. Other information included usually is: Next station, Route termination location, Major intermediary stops, weather (or at least temperature), car information (i.e. Quiet car, 1st class, etc) and service announcements. Amfleet IIs have LED scrolling bars in them, which may have the ability to show speed on them, although I've never seen one with such a feature turned on.

The closest I've come to an Amtrak train telling it's passengers what speed it was going was on a Wolverine. By chance I was on the 1st train approved to go at 110mph on the line, they made an announcement over the PA informing us.

peter

 

[john h]

there is a phone app you can download that will tell you your speed as long as you have a GPS signal

 

[PerRock]

there is a phone app you can download that will telkl you your speed as long as you have a GPS signal

Any GPS system (your smart phone has GPS in it) will tell you what speed, but they aren't exactly known to be accurate.

peter

 

[john h]

there is a phone app you can download that will telkl you your speed as long as you have a GPS signal

Any GPS system (your smart phone has GPS in it) will tell you what speed, but they aren't exactly known to be accurate.

peter

I never seen an issue

 

[caravanman]

To be fair, given the sedate speed of most Amtrak long distance trains, a calendar might be more use..

Ed

 

[ehbowen]

To be fair, given the sedate speed of most Amtrak long distance trains, a calendar might be more use..

Ed

Especially when on a siding, waiting for a freight...maybe even a "dead on the law" freight!

 

[trainman74]

Any GPS system (your smart phone has GPS in it) will tell you what speed, but they aren't exactly known to be accurate.

I never seen an issue

The inaccuracy comes because GPSes don't actually measure speed -- they measure time and distance and calculate speed from that.

But when you're a train passenger who just wants an answer to the question "how fast are we going right now?", the number being reported by a GPS is perfectly fine.

 

[Long Train Runnin']

I believe this information is displayed on Cascades trains.

 

[CHamilton]

I believe this information is displayed on Cascades trains.

That's correct, on the new Talgo VIII trainsets. This photo was taken during a tour before they went into service, so it's reading zero.

 

[AlexandriaVATraveler]

LOL at the person who says you can't measure speed using distance and time data. Physics 101: v=d/t

It's fair game to call into question the inherent error of GPS for location data (as is still and always will exist), but if a magical GPS gave you precise distance and time data, you could absolutely indeed calculate average speed between two points (in time or space).

After all, when the cop pulls you over, his radar gun "only calculates" speed based off of time and distance data. Try using your argument in court!

 

[andersone]

GPS isn't good enough for Government Work?

so much for advanced munitions

 

[Moonshiner]

I used a phone app on my recent SB Texas Eagle trip. I was regaling a couple with it in the Lounge and we were astounded to see speeds like 90 and even 140 at one point. Figured out later I had the app set to kmph. Haa!

Still I found it satisfied my curiosity about how fast we were going. Worked well.

I believe the app was called Speedometer.

 

[jis]

After all, when the cop pulls you over, his radar gun "only calculates" speed based off of time and distance data. Try using your argument in court!

Gee and here I was under the impression that the radar guns use Doppler shift to measure speed. Oh well....

 

[trainman74]

LOL at the person who says you can't measure speed using distance and time data. Physics 101: v=d/t

I think you might be referring to me. I said that GPSes measure distance and time, which they use to calculate speed (using the formula you have provided there).

It's been about two and a half decades since I was last in a physics class (honors physics in high school), but I still do remember that there is a difference between measuring something and calculating something.

 

[AlanB]

Actually when onboard the Acela's now, if you are using the onboard WiFi, the page that comes up after you agree to their terms will show you current speed, location, and the next stop.

Of course knowing how fast the train is going is only half the issue. One also needs to know what the track speed is for your area in order to know if the engineer is speeding. So in the case of the recent accident in Philly, even if people onboard had any idea of just how fast the train was going; most would have no idea that they were going too fast for the approaching curve.

And based upon the NTSB's timeline outlined earlier, even if one did know where they were on the line in the dark and that the train was going too fast, they would have had less than a minute and a half to do anything about.

 

[Guest]

Amfleet IIs have LED scrolling bars in them, which may have the ability to show speed on them, although I've never seen one with such a feature turned on.

How exactly does an Amfleet II car know its own speed? Just because there is a display, doesn't mean there currently is hardware on-board the car that can determine its speed.

 

[Ryan]

LOL at the person who says you can't measure speed using distance and time data. Physics 101: v=d/t

I think you might be referring to me. I said that GPSes measure distance and time, which they use to calculate speed (using the formula you have provided there).

It's been about two and a half decades since I was last in a physics class (honors physics in high school), but I still do remember that there is a difference between measuring something and calculating something.

You are correct, sir. Additionally, since you're calculating it over a time interval, it's impossible to know your instantaneous velocity, only your average velocity over the previous time interval.

 

[OlympianHiawatha]

While an on board speed display would be interesting for some pax, including most of us, most pax probably could care less, making the costs of installing and maintaining such a system a frivolous expense, especially as tight as the Amtrak budget Kitty is.

 

[AmtrakBlue]

And I imagine seeing 125 on certain stretches would scare some people. Especially after this recent tragedy.

 

[StriderGDM]

And I imagine seeing 125 on certain stretches would scare some people. Especially after this recent tragedy.

No, far more likely it's seeing all the 25mph and 35mph that would frustrate people.

 

[Bierboy]

there is a phone app you can download that will telkl you your speed as long as you have a GPS signal

Any GPS system (your smart phone has GPS in it) will tell you what speed, but they aren't exactly known to be accurate.

peter

I never seen an issue

Nor have I...they're usually pretty accurate. And it's very simple to calculate if it's accurate while traveling in an automobile -- you watch the mile markers and the clock. It's pretty simple physics/science...

 

[Ryan]

How exactly would you know if you did see an issue, unless you have a calibrated speedometer next to it for comparison at all times?

 

[jis]

While an on board speed display would be interesting for some pax, including most of us, most pax probably could care less, making the costs of installing and maintaining such a system a frivolous expense, especially as tight as the Amtrak budget Kitty is.

I have seen them in each car of the granddaddy of all high speed trains, the Japanese Shinkansen system. The Northwest Cascade new sets have them too as do many other HSR trains. It really is not a huge additional expense anyway. But yeah I know, we do everything real cheap and still it costs us more than it costs anyone else to do the same thing.

 

[Oldsmoboi]

How exactly would you know if you did see an issue, unless you have a calibrated speedometer next to it for comparison at all times?

The app I use has a HUD mod where everything is displayed in mirror image. It is meant to put on your dashboard of your car and then it reflects on your windshield. I've used it a few times because it also displays navigation data.... but lining it up with my car's speedometer, it seems to be pretty accurate. The only time there was a delta between the app and my car was when I was accelerating faster than the app would respond. Once a constant speed was reached, the readings would sync to within a MPH of each other.

 

[Ryan]

That's a pretty awesome feature.

At ~60 MPH, the GPS consistently reads about 1 MPH slower than the speedometer. I assume that's an intentional speedo calibration thing to ensure that you're not going faster than the speedometer reads.