Railserve

RailServe.com: The Internet Railroad Directory - Guide to 17,000 rail-related websites including train travel, model railroading, railfan resources, train simulators, and railroad industry sites

ModelRailroadForums

ModelRailroadForums.com is a free online Discussion Forum and photo gallery. We cover all scales and sizes of model railroads from Z scale to ride on live steam. Our discussions cover a wide variety of topics including layout design and construction, locomotives and rolling stock, wiring and DCC, kits, scratchbuilding, details, scenery, benchwork and many more. Whether you're a master model railroader or just getting started, you'll find something of interest here.

Trainboard

This website has N-Scale as a primary focus.