The Railway Museum, Saitama

Any idea how to reserve the the steam locomotive simulator in advance? thanks

You have to do it in person at the museum. Reservations start from 10:00 at the simulator room on a first come first serve basis.

No reservation as before days.
All game players make a waiting line museum open 10am before at out side.

If enough money and time flight to China (not west Japan "Chugoku" area)
you can operate real big one :D
http://youtu.be/lSkGx1uD000

In Japan(Wakasa and Mikasa) also possible but not long way and time
http://site5.tori-info.co.jp/p/chizukyu/guide/yazu_wakasa/sl/
http://www.s-304.com/main/club/
Electric loco/car, diesel car,too.
http://matome.naver.jp/odai/2138970432769680401
http://matome.naver.jp/odai/2138970432769680401?page=2

Thanks.

For the Reservations, any idea how should i go about it? will there be queue form that i go join in? thanks

There are cones set up outside the entrance and are maintained by the staff as the waiting line gets longer. You can inquire at the line, but if you don't know Japanese, they won't be able to help you. The simulators are on the second floor, roughly above the entrance. If you walk fast, you can be one of the first in line. But, like I said before, if there are school groups, they may have reservations. I really don't know about that one.