wait, why are you building the this tunnel again?
EDIT**** sorry, i mixed the quencher and retort in my head.....
The Coke oven doesn't have to be on site either. Often times these businesses situate themselves near where there are many steel mills (often times they don't even belong to a steel mill). they aren't a part of the Blast furnace/rolling mill area. I think you should just either make more space for the coke oven, or remove something you don't want.
or just leave the coke oven out. it doesn't neceisarrily need to be on the layout. The only buildings you need is the Blast Furnace, because thats the one everyone identifies with a steel mill. You should add the rolling mill because its an intersting part of the complex that would be there.
The only other thing you need, is a track with a pit for coke hopper, and a track for the rolling mill. Thats all you need for that corner of the layout. The other steel mill buildings wouldn't be there, they are just part of the process. It would be unreslitic in real life to have a coke oven right there on site ( although the coke ovens try to stay close)
Also, Usually a steel mill has its own little industrial railroad. The main railroad ( in you case BNSF) would only ship cars in bound to the steel mill, and cars leaving the steel mill.
You'd only need a track that goes off behind a building and call it an interchange track.
If you do ever get the space though, i reccomend buying a small swithcer (like Bachmann's GE 70 ton switcher, or an early EMD switcher with a low cab) as these are the locomotives that would have worked on a the insides of a steel mill, not your big B40-8.
so there you have it, 3-5 tracks. 1 or 2 that go over the coke pit, 1 or 2 for the rolling mill, and another track for other inbound cars. thats all you need to put in that corner, and it will probably fit better. save the coke oven for another day.