This is just like a travel guide. Great looking magazine.
Even though I can’t afford to buy, maybe someday,I offer these suggestions:
1) Train station gifts:
keychains,station signs, pen&stationary train models and their mascots, need to find one for Rilakkuma
2) Affiliate programs, like w/j-list.
3) Travel guides; like the Brutus magazine and others associated with it or videos.
4) Conbini merchandise, could maybe work out a deal w/the local ones in your neighborhood,giving them exposure like you do during the conbini mondays.
These are just mho anything I can help to do to promote your site.