Hello Choochooglen and welcome to the forum. I assume that you mean Rotherham rather than Rotterdam? Can I suggest that you put the address into google maps, that will give you an excellent view of the scrapyard and help with getting the track plan right. Also there are websites for C.F.booth, and
www.rollingstockcomponents.com that might be helpful. For the model slag car try
www.ontracks.co.uk they stock a trix model (pack of 2) but you might wince a bit when you see the price!
Hope this helps.
Cheers, 62440.