[AC Question]

I recently downloaded some train timetables in pdf form. I wish to save one of each on my S4.
I can view the download by sliding down the screen & clicking on the folder but after closing it vanishes. There doesn't seem to be any "save" option as one get on a PC.

do I have to download pdf files afresh each time I want to look at one or can I save them on the phone?

[SpookDroid]

You should be able to save them to the phone. Where are you viewing the PDF files from are which app are you using to view them? If it's from a link, it should actually save the file to your phone when you click on it (and you'd find it in the DOWNLOADS app of your phone, which is a shortcut to that folder). If you are downloading it from an e-mail, the file will temporarily download if you select the PREVIEW option, but there should be a SAVE option there, too.