Ed,
Years ago, an employee of Commercial Metals compiled a listing of rail then known that covers the gamut from the smallest to the largest, shows the mfg and measurements of many different sizes of rail, and even the differences in the same size (900, 901, 902, 903, 904..).
I will send you a copy f you will give me your mailing address. it is about 15 double sided, legal paper size.
Offer good for anyone else wanting a copy.
PM me.
Harry