This is what I was thinking of.
There are some good formulas for this in Wikipedia which should be simple enough for, I'll have a hunt for them and post what I find.
About this website
Railpage version 3.10.0.0037
All logos and trademarks in this site are property of their respective owner. The comments are property of their posters, all the rest is © 2003-2020 Interactive Omnimedia Pty Ltd.
You can syndicate our news using one of the RSS feeds.