Resources for realism

North America

United States

• Rail.guide is a very useful tool for specifically American rails. While it isn't often the most accurate, it really depends on the region. Rail.guide often has data which ORM lacks, especially for historical data (either Current-Classic, Classic Owners or Early Owners map modes, abandoned is useful as well) which is by far the best feature of this website.
• Nashua City Station is a railroad history website that provides very accurate and useful historical railroad data for mainly states in the New England region of the U.S. whether you want to know the exact location of a random station in Rhode Island or just want to see what trains used to run to Worcester, MA, this website has your back.
• The Library of Congress has a large collection of historical railroad maps, the site can be hard to navigate but it's very useful.
• American-Rails is a very useful site for U.S. railroad information, specifically historical. There are articles for almost every "Fallen Flag" of U.S. railroads, each one written in great detail often including a detailed map of the railroad at its peak, with other useful data to work from as well.
• Vanshnookenraggen creates many highly realistic track maps for U.S. transit systems such as Chicago's "L" and the New York City Subway, as well as creating historical track maps and track maps with planned extensions built out.
• Timetable World's Official Guide of the Railways collection provides historic passenger timetables for all of North America from 1868 to 1971. Follow guidance on the page for information on how to access the free online viewer.
• Wx4's Historical Maps & Timetables archive contains a very large collection of
• Multimodalways provides an assorted archive of rail (and other) documentation.

New York

New York City

• nycsubway.org is an excellent website with a large collection of New York City Subway track maps and track diagrams both historical and up-to-date. The website also has a very comprehensive history on the New York City Subway.
• Vanshnookenraggen's New York City Subway Track Map See, first entry for why.

Illinois

Chicago

• GreatThirdRail.org is the best site for anyone wanting to recreate the Chicago, Aurora & Elgin interurban railroad. This site specifically covers the CA&E and in great detail, providing very high quality historical maps and timetables, accurate station locations, anything you would really need to recreate the CA&E.
• Chicago-L.org is the best site for information about the Chicago L, past, present or future. The amount of data on this site is extraordinary and I would highly recommend this website in addition to Wikipedia.
• Wikipedia's Chicago "L" system (all time) Track Diagram. While Wikipedia is already on this page, this track diagram is especially useful for Chicago's "L", it should be noted that this track diagram contains all of the tracks past and present on the system, along with almost all stations having a dedicated article.
• Vanshnookenraggen's Chicago "L" Track Map See, first entry for why.