Don't understand that as the rail is one piece of pipe ie. 'common rail'

As said, it will be full of air, you need to prime the low pressure side before it will ever start, but if its been tried to start full of air it will be even harder to get running.

Once the low pressure side is primed you can try running it on brake cleaner/easy start so it will 'pick up' and then run on its own..be careful spraying too much in the intake of course....

One these have air in , they can be a bugger to get going..the trick is always to make sure its primed before you try starting it, but it's too late for that....