These are the model railway and railway magazines on Hobby Search.
http://www.1999.co.jp/eng/list/827/0/1These are either National Geographic size or large oversize magazines.
Japan Railfan Magazine is probably the best of the railroad magazines. It has fold-out car plans for new equipment each month at the back of the magazine. There is nothing comparable to a North American model railway magazine from I've found. Most model magazines just focus on models, not layouts or scenery.
Beware these magazines are heavy, therefore shipping is expensive (2,765 to 4,896 Yen) on orders I've placed. By comparison shipping a Tomix catalog runs 5900 Yen for shipping.