most scenic rail routes

I am a railway enthusist and i plan a Japan trip for next september. I would like to ride JR trains on the most scenic rail routes (mountain railways or coastal railways, or railways through beautifull landscapes)

if you're in the Kyoto area, I remember there was this train near Arashiyama and it was a scenic train. I forgot the specific name, I didn't ride on it, but it's a train made just for looking at scenery.

Note that not all trains in Japan are "JR Trains", "JR" means a specific railway company "Japan Railways" (or rather a series of JR railway companies). Sorta like how Japan Airlines is just the name of one airline in Japan, not th e name of all the airlines in Japan.

There maybe many routes that are fantastic but not operated by JR trains.

We took the JR ltd express from Nagoya to Matsumoto and it was quite scenic. However, it's also a bit like a carnival ride in places and half the train appeared motion sick upon arrival!

JR TADAMI line in Fukushima prefecture (in the mountains)
http://www.sssoft.net/tetu/contents/200311touhoku.html#tadamisenn

JR GONOH line from Akita to Aomori prefecture (along the Japan Sea)
http://kandelaar.huuraibou.com/archives/2006/06/post_301.html

The train in Arashiyama, Kyoto is called the Sagano Romantic Train.

I rode on this train last year, which takes you through a mountain range along a river and through tunnels. It is quite scenic, but the trip is only about 15-20 minutes. Still worth it if you plan to visit Kyoto.

http://www.japan-guide.com/e/e3912.html#romantic

The tram/railway through the Kurobe Valley (Toyama Prefecture, near Takayama, Kanazawa) is something that I wish I had had the time for. JNTO's description sounds unbelievable.

http://www.jnto.go.jp/eng/location/regional/toyama/kurobe.html

Of course it's not a JR train but it's still pretty cool.

I live near Tokyo so the Enoden line, also not operated by JR, in Kamakura is considered a pretty beautiful ride. Definitely pretty scenic.

. . . mentioned earlier, the Keyakadaira train ride is probably Ichiban in this respect. No doubt it's fantastic in autumn. The train basically goes out and back. On the way out sit on the right side, on the way back, the left.

#2 on the list probably goes to the train to Ikawa Dam (Oigawa Railway). Again, best during autumn, but difficult to time. The train actually pauses at a couple of places for people to take pics. Detailed info is on the JNTO site. Ikawa is known for shiitake mushrooms, which you will likely be served at ryokans.

Both train rides involve some open cars riding over pretty red bridges. On the Keyakadaira ride, I spotted a Japanese mountain goat along a river basin.

One problem with the Gono Line during winter, is the train has huge picture windows which are not double pane. So they fogged up horribly the whole trip. I did bring a Rain-X cloth, but it doesn't work well on wet glass.

JR publishes a lot of literature on scenic train rides, some by locomotive, which you can find at the JR stations. Only in Japanese. I believe they are located in the Niigata or northern Tohoku area. The pamplets detail siteseeing attractions and special places to eat at each stop.

Speaking of locomotives and closer to Tokyo, the ride on Chichibu Railway is also very scenic. It follows a gorge in many areas.