Many moons ago I was given a book by an aged Aunt, it was titled ‘Something To Do’. In it had lots of ideas. The pink cover put me off because it was a girls colour but when Mum flicked through it and found how to make a hill for you model railway. Many years on a trip somewhere Mum had squirreled away the book and on a train trip showed me the following article:

Things to do in the Train.

*Check The Speed*

This only needs a watch with a second hand and a little arithmetical division. If you look out of a train window you will see white posts about a meter high with black numbers set at regular intervals besides the ‘downside’ track (though the posts and markings vary slightly from region to region).

The posts are actually at 1/4 mile intervals and if you note the number of seconds it takes to travel from one signpost to the next you know how long it takes the train to travel a quarter of a mile., By dividing this number of seconds in to 900 you can then work out the speed of your train in miles per hour.

i.e. Let *x* be the number of seconds it takes the train to to cover the distance between two consecutive posts.

x seconds for 1/4 mile = 4*x* seconds for 1 mile.

There are 3600 seconds in one hour.

Therefore miles covered in one hour (i.e. speed of train)

= | 3600 | = | 900 | m.p.h. |

4x |
x |

If, for example, you find the train takes 9 seconds between two 1/4 mile posts, the sum is then 900 ÷ 9 = 100 m.p.h.

To convert m.p.h. to kilometers use the following table:

m.p.h. | 40 | 50 | 60 | 70 | 80 | 90 |

km.p.h. | 65 | 80 | 97 | 113 | 129 | 145 |