aeroplane is right on the brake-lever-to-caliper compatibility issues. The other issue you may run into is handlebar diameter; MTB bars are generally narrower tubes than road bars. I assume track bars are basically the same size as road bars in this respect but I don't know. Anyway, some MTB levers are too small to fit on road bars. But the recommended CX "inline" lever is designed for road bars and works great. You should be able to use your existing cable and caliper as they are, since the cx lever will take less cable than the road lever.