This is mostly a page to guide you to other sources of information. Rather than trying to put everything up myself, I've used the linking nature of the Web to show you what the best sites I've found are.
Another navigation aid, but for New York City's borough of Manhattan only, is this one. And you don't even need forms for it. It'll tell you the nearest subway station (or stations) to any street in Manhattan.
New York City has a web page describing its Transit Museum, which I've found interesting. Another transit museum, the Museum of Urban, Interurban, and Rural Transport in France, has a good web site if you can read French.
A survey of rail and trolleybus systems worldwide , a survey of Canadian transit systems (past and present), and a survey of Canadian horsecar and trolley systems (past and present) are maintained by David A. Wyatt. The last two of these have detailed historical notes on each system, clickable from the lists. Robert Reynolds has collected together a variety of subway maps, many including commuter rail or light rail as well, usually comprising multiple maps for each city. And Robert Bowdidge has put up a site with some useful railroad and transit links.
The National Transit Library is maintained by the Government on the Web.
A collector of transportation tickets has put a display on the Web.
There is also a Usenet newsgroup on transit.
Some transit systems have their own (official or unofficial) sites now. I've made an alphabetical listing below. I want particularly to thank Geordi Byron (a/k/a Arete) for performing searches that provided the large majority of the links in the list. As I get them, I will add more URLs to this list:
= A = B = C = D = E = F = G = H = I = J = K = L = M = N = O = P = Q = R = S = T = U = V = W = X = Y = Z =
You can help me by sending me additional URLs for this page. In addition, if any of the links do not work, please mail me the details.