There are lots of threads on shooting white backgrounds, some long and detailed.
Basically, this technique is not easy, though the Hilite makes it much easier as well as saving a lot of precious working area. The trick is to get the background as evenly lit as possible, and then just/I] over expose it so that it blows to white.
With care, that can be done okay but when it comes to lighting the train - which is obviously impossible to over expose without over exposing the subject with it - that's when clever tricks like reflective floors come in and/or bit of jiggery pokery in post processing.
In other words, have a go with head portraits and three-quarter body shots first, then when you've got that nailed, add the train and try for full length, kids on the floor etc.