Some of my iTunes Library duplicate tracks but they point to the same file only the added date is different

It points to you having re-imported chunks of your library again - maybe when transferring to a new device - or something's gone wrong with a consolidation at some time.

A quicker way to delete would be to use Songs view, add the Date Added column, sort by added date and then you can bulk select  and delete - which will speed things up a bit

If there's an obvious separation between the added dates across all your albums (the examples you show are years apart) - or they are all the same for one set then you could create a smart playlist filtered by Date Added which only contains duplicates and then delete them all at once - but you'd have to be careful. If I were you I'd make sure I'd got a good backup of the media.  

I'd hang on a couple of days in case a user called Turing Test comes along cos they are very clued up on iTunes and might have a better idea of what's gone on.

Best of luck!

Sorry - I'm not thinking. File/Library/Show Duplicate Items will show all the duplicates in a playlist or the whole library, depending on what you're looking at. It would be a quicker way to find them, but you'd still have to sort them as above. I'd start by showing the duplicates for your whole library using this then adding them to a playlist called, say, myDuplicates. You could then inspect at your leisure and work out the best way to delete the ones you don't want - either just by sorting it based on date added or something cleverer with a smart playlist.

Note that the Find Duplicates just goes on the track name. If you've changed a track name (e.g. I put a * at the end of bonus tracks) then it won't find them. It will also think that the same title by different artists is a duplicate, so you'll still have to be careful. If you use songs view with Album art always showing and sort your myDuplicates playlist by title then you can spot this because by looking for artwork. It's quicker than you think.

I'd still hang on for Turing Test, though.

If you right click on the track and click "Show in Finder" do the duplicate tracks definitely point to the same file?

So, to be clear, when you right click and show in finder and it opens a finder window then both tracks show the same file in the finder window.