My recent trip (Oct 2014) to Central Japan also covered famous moutain sighseeing route between Tateyama - Kurobe. The scene appear to be different in each season. Yukino-ōtani is the most famous sightseeing spot from April to June. You can enjoy the greatest snow walls just before Murodō along this route. The month (Oct - Spring) I went I don't see the ice wall.
The Northern Alps route is 25km long , the vertical (height) is as large as 1,975m.
It uses 7 different modes of transport to complete the route, which including cable car, bus, trolley bus, ropeway, aeriel tramway.
Source : Alpine Route
The route is carefully built so that the surrounding environment is not damaged. Consequently, three lines go entirely under tunnels. (This is also to protect the lines from snow.) Among them, two are trolleybus lines. I just read from Wiki that Trolleybuses have all gone from Japan, except for these two lines which are still used here as they don't exhaust fumes in the tunnels.
photo credit : Lay Hoon