Running out of columns and can't add multiple pivottable fields simultaneously

[mrwnt10]

I have a table of delivery orders, with start and end times (see attachment). I am trying to figure out the maximum number of deliveries that happened concurrently. The order times are to the minute and the orders span multiple days.

I tried creating columns for every minute and day combo, but ran into the Excel columns max. Next I tried just creating columns for every minute and using a PivotTable to separate by day, but there are 24 hours * 60 minutes/hour = 1440 minute fields to add, and I can't figure out how to add multiple fields at once.

I've searched online for solutions to both of these problems to no avail. Does anyone have any suggestions, or alternative ways to solve this problem (since I suspect I'm just approaching it incorrectly)? I would appreciate any assistance!

[FDibbins]

Excel has far more rows than columns, try going down instead of across (although why you would want to take that approach is beyond me)