Placing the Advanced Detector Rail next to the Detector Unit Blocks also seems to have no effect. I've watched all of the available videos on youtube and everything, including the 40 minute video on the Steve's Carts Website (http://stevescarts2.wikispaces.com/Detector Units), each of which have the blue Advanced Rail on top of the Detector Blocks.
Here's 2 pictures I took, showing the set up. Super Basic, and neither of them work. The 2nd picture, with no blue advanced rail, is showing how I can't get it to go on the detector block. (http://imgur.com/a/OqNHS)
I really don't know what else to do. I've tried switching Forge versions, I've removed all mods except this one... No results. Was this functionality taken out? Or am I just derping really hard here? Am I even doing this right? I can put other blocks on them. Grass, stone, whatever. But no railway tracks of any kind will sit on ANY of the detector blocks.
Really lost here.

Edit: Versions:
Minecraft Version: 1.7.2
Forge Version: 1.7.2 - 10.12.2.1121
Steve's Carts 2 Version: 1.7.2 Beta 15
1
I think the problem is this Buildcraft's migration from MJ to RF that's effecting all MJ dependent mods. Probably smarter to down grade your other mods and hold off updating until all the major bugs are sorted out.