Splitting Multiple Days From a Data Set?

So here is my problem... I have a very large and very basic data set which includes 4 columns of data (production line #, order #, date started, date finished). I'm trying to manipulate the data to compare when certain pairs of production lines are running at the same time. A lot of the orders only run for a part of a day and for those I could just use the starting date for comparison. If I just use the starting date for the other orders though, I will miss the days when a line ran for more than one day on a particular order. Is there a way or formula that anyone knows to add lines of data for the other days of these multi-day orders so I can accurately compare the data by date? I basically just want to know whether a particular line ran during a particular day of the year, but how do I get that from the data set I have to work with? If anyone has any thoughts or guidance, I'd greatly appreciate it.

Thanks

Here is a small sample

In this instance Line 9 shows an order that was run from 3/31 until 4/2. By just using a start date, I lose the information that line L10 also ran on 4/1. How do I get this to count as a "run day".