How do you remove a cummins 24 valve cascade overflow valve?

On my 03 5.9 it is very easy the valve is just behind the air intake horn on the fuel rail a 3/4 inch wrench removes the upper bolt that holds return line in place and a bit larger wrench will remove the valve from the rail WARNING. be very careful that the engine isn't running even at idol R.P.M there is about 4500 P.S.I in the rail

The above answer is wrong.

The Cascade Overflow Valve can be found on the injection pump. Look at the injection pump you will see two lines attached with banjo bolts, look at the line closest to the front of the truck. Just to the right of that line you will see the cascade overflow valve. Use the appropriate size wrench to remove it.