Dunno if its the right place to post this issue, the Railcraft Irfonfurnaces are the same as the normal Furnaces except they are faster. I replaced one nomral through it and found out that a Gate I had directly on a pipe on the backside should trigger a signal as soon there is coal in the ofen (works perfect with normal furnaces, with the iron one, the signal always get triggered if there is something in the output).

Ups I've ment the Iron Furnace from Industrial Craft²/GregTech "http://feed-the-beast.wikia.com/wiki/Iron_Furnace"

BC_NotMyFaultException, we go by ISidedInventory

I believe that's because the RailCraft Iron Furnace uses ISidedInventory, while Minecraft's Furnace does some weird things (like a lot of vanilla). @CovertJaguar ?

You mean the steam oven : P

Well that one missed the mark by a fair bit, lol.