How to add column that shows start/finish time in minutes?

I see you can list a task in minute increments, e.g. 15min. We are creating a cutover plan and need to list a start & finish TIME: e.g. 9:00, 10:00, etc. Does Smartsheet have this as an "intelligent" column or just a text/number one only? Would be extremely helpful, so that folks can time the work and also, if you add another task, the timing would update.