RAILforum: Speed Chart

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Posted by JONATHON (Member # 2899) on :

Back in the old days, as you know, they would check the speed by timeing how many seconds between Milepost, and using a small chart/card that says the speeds, an depending on how many seconds between milepost, you read it and see what amount of seconds means what speed,,

Anyway, where can I get one, if anyone knows, please reply!

Thanks

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JONATHON D. ORTIZ

Posted by Sheriff (Member # 2521) on :

Johathon;
Most of the railroad tracks I worked on had 30 telephone poles to a mile. There was one metal band around the tenth pole, two metal bands around the twentyth pole. and sometimes when there were 33 poles in a mile, there would be three metal bands around the thirtyth pole. This way you could clock your speed by only using the 10 poles. You just divide by 3. We also used the poles for locating a certain car in the train, or how long our train was (20 poles long= 2/3rd's of a mile).

Some of the old personnel log books had the chart in the back. I'm talking about the book the union usually gave you to keep track of your trips, times, and how much money you made for that trip.

Posted by Ira Slotkin (Member # 81) on :

Jonathon, if you were of a mind to, you could make your own easily. It's just division and mulitplication. Word problem.

A train going sixty miles per hour goes a mile in one minute. A train going thirty miles per hour goes a mile in two minutes. A train going two miles per minutes is going 120 mph. You can combine this with Sheriff's pole info, as well.

I remember riding the National Limited from St Louis to New York many years ago. I used to stand in the vestibule between cars, look out the window and time the miles with my watch.

You can practice in a car on the Interstate using those mileage post while someone drives at a steady speed. Good luck.

Posted by George Harris (Member # 2077) on :

If you have any employee timetables, a lot of them will have a table like tis, usually on the back. However, with a computer it is real easy to make this table in excel.

Advance apologies for writing this on the excel for dummies level.
To calculate your own speed table in excel, set your speeds in one column, let us say column B. To be lazy, if you enter 1 in cell B3, for example, then put =B3+1 in cell B4, then copy and paste down as many rows as you want. Then in cell C3 enter =3600/B3 Then copy and paste down as many rows as you have numbers in column B. Write some headings above this so that you can remember what each column means. Since this becomes long and skinny, you can maybe go 1 through 40 in columns B and C, 41 through 80 in D and E and 81 through 120 in columns F and G. Do format number, go to number and set the number of decimal places you want to see. When you do this, you will see very large numbers of seconds for low speeds.

You can make the numbers easier to understand if you make it in minutes and seconds for the lower speeds. It has one more step in the process. Make three column heading, say in B2, write speed, in C2 write minutes, in D2 write seconds. Again, in B3 write 1, in B4 write =B3+1 Go to D3 and write =3600/B3-c3*60 then copy D3 to D4. Black B4 C4 D4 and copy row into B5 and as far down as you want to go. In C3 write 60 You will see D3 go to 0 In C4 write 30 and you will see D4 go to 0 You can continue on down guessing minutes or you can have excel calculate them and then go back and fill in with whole numbers. If you guess the minute and the number in column D goes negative, then use a smaller number in column C until the number in column D goes positive. If the number in column D is greater than 60 use a larger number in column C until the number in column D goes below 60. Again, you can fold the table and set a format on the seconds column. Since the minutes column must be exact minutes there is no need to set a number format on the minutes.

OK, I know I wrote this on an elementary school level, but since I do not know who all will read this, I though it better to leave no step out rather than omit what I think is obvious that might not be obvious to some of the readers.

Posted by Mike Smith (Member # 447) on :

Excel????

What's an "Excel"?

I check the train speed the old fashioned way... I pull out and turn on my GPS. It shows me exactly where we are and how fast we are traveling.

Posted by RRRICH (Member # 1418) on :

Mike - Excel is a very common and popular computer spreadsheet program, and is included if you have Microsoft Office on your computer system.

Posted by Gilbert B Norman (Member # 1541) on :

I don't "exactly" think "breaking out my GPS" is checking speed the old fashioned way.

Most, if not all, steam locomotives were delivered without speedometrs. The one time I was in the cab of one was at Hervey, PQ during August 1956; I did not see one about. The CN fireman (fluent in English) said you just look at the poles to tell how fast you are going.

But oh well, back then authorized speed was "quite open for interpretation".

Posted by Mike Smith (Member # 447) on :

Oops... I forgot the "facetious" insert into my previous post... :P

And "old fashioned way" = what I did this time last year...

Posted by rresor (Member # 128) on :

Two cautions, one on GPS and one on mileposts.

GPS measures speed by calculating how long it took to go from the last lat/long location to the current one, and what the (straight line) distance is. That could introduce errors on track with many curves, especially at high speeds.

Mileposts are, for a variety of reasons, frequently more or less than a mile apart. On the NEC there are some really short miles due to line relocations (say 4000 feet or less). Timing *those* mileposts will make you think you're going really fast.

Employee timetables usually indicate "test miles", miles that are more or less exactly 5280 feet long. Time those for an accurate speed calculation.

Posted by Geoff Mayo (Member # 153) on :

Two questions:
1. How accurate are GPS speedos these days? I remember they had a built in location inaccuracy factor, supposedly for "security reasons". So your speed could also be out by a factor too. Is this still the case?

2. What about defect detectors? I'm aware they can't always count axles very well ;-) but how accurate are their speedos? And what speed - the front, rear, or average of the train, since it could be slowing down or speeding up as it passes.

Geoff M.

Posted by George Harris (Member # 2077) on :

The security factor is not quite what it once was, but do not knwo the exact limits, however on one project of which I have knowledge, one meter resolution mapping was offered based on former Soviet sattelite mapping. Since it was not purchased, I have no idea how well it would have matched up to the results of an on-ground survey.

Considering the usual one second to half second at best accuracy you can get with mile posts, eye-hand coordination and a stop watch, any accuracy of 10 m or less by GPS would be better than you could do by watch, hand and eye, assuming of course a straight track. (Even 30 mph is 44 feet per second, so a half second off mans you missed the mile by 22 feet.) As RRESOR pointed out, there may not be 5280 feet between mileposts. Usually there is, or close.

Posted by a4ester (Member # 3147) on :

Another easy way to calculate speed is to divide 3600 by the number of seconds it takes to travel one mile. Again it is only accurate if the mile posts are indeed 5280' apart. I use this formula to check the speedometer on a vehicle.

Posted by rresor (Member # 128) on :

This is a bit off topic, but the GPS inaccurary mentioned above was known as "selective availability". To deny GPS signals to hostile forces, the military reserved the right to introduce a random "dither" into the GPS signals, which greatly reduced positioning accuracy.

President Clinton ordered that selective availability be discontinued as a policy, so it's not done anymore.

Use of "differential" GPS, now available nationwide, increases GPS accuracy to about 3 meters (of course, accuracy and speed are inversely related -- left in one place long enough, a GPS unit can get to within a few centimeters of its true position).

Posted by JONATHON (Member # 2899) on :

Can some one please post the times and speeds or post the chart

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JONATHON D. ORTIZ

Posted by Geoff Mayo (Member # 153) on :

http://www.bnsf-ttc.com/bnsftime/

Click on "I accept", then select one of the timetables (eg Chicago), then the link at the top of the page. On the last page is the speed chart you're looking for.

Geoff M.

Posted by George Harris (Member # 2077) on :

I am going to try to past in one of my charts. This is a table in word. If this does not work, or is incomprehensible, email me and I will send it as either a word file or excel file, name your preference. Use a subject line that assures me this is not some randomly generated email with a virus or sales pitch. Those I kill without opening.

Better just email me. the attempt to copy in did not work well.

[This message has been edited by George Harris (edited 03-26-2004).]

Posted by George Harris (Member # 2077) on :

I am going to try this one more time: I will still email the table to anyone who asks.

m = minutes
s = seconds

----0 m 30 s = 120 mph
----0 m 31 s = 116 mph
----0 m 32 s = 113 mph
----0 m 33 s = 109 mph
----0 m 34 s = 106 mph
----0 m 35 s = 103 mph
----0 m 36 s = 100 mph
----0 m 37 s = 97 mph
----0 m 38 s = 95 mph
----0 m 39 s = 92 mph
----0 m 40 s = 90 mph
----0 m 41 s = 88 mph
----0 m 42 s = 86 mph
----0 m 43 s = 84 mph
----0 m 44 s = 82 mph
----0 m 45 s = 80 mph
----0 m 46 s = 78 mph
----0 m 47 s = 77 mph
----0 m 48 s = 75 mph
----0 m 49 s = 73 mph
----0 m 50 s = 72 mph
----0 m 51 s = 71 mph
----0 m 52 s = 69 mph
----0 m 53 s = 68 mph
----0 m 54 s = 67 mph
----0 m 55 s = 65 mph
----0 m 56 s = 64 mph
----0 m 57 s = 63 mph
----0 m 58 s = 62 mph
----0 m 59 s = 61 mph
----1 m 0 s = 60 mph
----1 m 1 s = 59 mph
----1 m 2 s = 58 mph
----1 m 3 s = 57 mph
----1 m 4 s = 56 mph
----1 m 5 s = 55 mph
----1 m 6 s = 55 mph
----1 m 7 s = 54 mph
----1 m 8 s = 53 mph
----1 m 9 s = 52 mph
----1 m 10 s = 51 mph
----1 m 11 s = 51 mph
----1 m 12 s = 50 mph
----1 m 13 s = 49 mph
----1 m 15 s = 48 mph
----1 m 17 s = 47 mph
----1 m 18 s = 46 mph
----1 m 20 s = 45 mph
----1 m 22 s = 44 mph
----1 m 24 s = 43 mph
----1 m 26 s = 42 mph
----1 m 28 s = 41 mph
----1 m 30 s = 40 mph
----1 m 32 s = 39 mph
----1 m 35 s = 38 mph
----1 m 37 s = 37 mph
----1 m 40 s = 36 mph
----1 m 43 s = 35 mph
----1 m 46 s = 34 mph
----1 m 49 s = 33 mph
----1 m 53 s = 32 mph
----1 m 56 s = 31 mph
----2 m 0 s = 30 mph
----2 m 4 s = 29 mph
----2 m 9 s = 28 mph
----2 m 13 s = 27 mph
----2 m 18 s = 26 mph
----2 m 24 s = 25 mph
----2 m 30 s = 24 mph
----2 m 37 s = 23 mph
----2 m 44 s = 22 mph
----2 m 51 s = 21 mph
----3 m 0 s = 20 mph
----3 m 9 s = 19 mph
----3 m 20 s = 18 mph
----3 m 32 s = 17 mph
----3 m 45 s = 16 mph
----4 m 0 s = 15 mph
----4 m 17 s = 14 mph
----4 m 37 s = 13 mph
----5 m 0 s = 12 mph
----5 m 27 s = 11 mph

Posted by JONATHON (Member # 2899) on :

Thank you!

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JONATHON D. ORTIZ